| 1. |
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- 2019
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Journal article (peer-reviewed)
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| 2. |
- Xia, Yangyang, et al.
(author)
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Prediction of bending strength of glass fiber reinforced methacrylate-based pipeline UV-CIPP rehabilitation materials based on machine learning
- 2023
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In: Tunnelling and Underground Space Technology. - : Elsevier. - 0886-7798 .- 1878-4364. ; 140
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Journal article (peer-reviewed)abstract
- Ultraviolet cured-in-place-pipe (UV-CIPP) materials are commonly used in trenchless pipeline rehabilitation. Their bending strength is a crucial indicator to evaluate the curing quality. Studies show that this indicator is affected by multiple factors, including the curing time, UV lamp curing power, curing distance, and material thickness. Laboratory experiments have limitations in analyzing the effect of multiple factors on the bending strength of UV-CIPP materials and quantitatively predicting the optimum curing parameters. Aiming at resolving these shortcomings, resolve machine learning techniques were applied to predict the bending strength. In this regard, the surface curing reaction temperature monitoring data and three-point bending data of 30 groups of UV-CIPP material under the influence of different curing parameters were used as a dataset to predict the bending strength of UV-CIPP material. The results show that the influence degree of each factor on the bending strength of the UV-CIPP material, from high to low, is as follows: UV lamp power (−0.439), the temperature at the illuminated side (−0.392), curing time (−0.323), the temperature at the back side (−0.233), curing distance (0.143) and material thickness (−0.140). The best penalty parameter c (44.435) and width g (0.072) of the kernel function in the support vector machine (SVM) model were obtained using the genetic algorithm (GA) optimization, and the results were compared with the grey wolf optimizer (GWO) and particle swarm optimization (PSO). The performed analyses revealed that the developed GA-SVM model exhibits the best prediction results compared to other machine learning algorithms. The optimum bending strength of the UV-CIPP material used in this test is 294.77 MPa, which corresponds to the curing time, UV lamp power, curing distance, material thickness, light side temperature, and back side temperature of 7.59 min, 157.33 mW/cm2, 189.99 mm, 4.38 mm, 79.49 °C, and 76.59 °C, respectively.
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| 3. |
- Yu, Wenjin, et al.
(author)
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Deep Learning-Based Classification of Cancer Cell in Leptomeningeal Metastasis on Cytomorphologic Features of Cerebrospinal Fluid
- 2022
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In: Frontiers in Oncology. - : Frontiers Media SA. - 2234-943X. ; 12, s. 1-11
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Journal article (peer-reviewed)abstract
- Background: It is a critical challenge to diagnose leptomeningeal metastasis (LM), given its technical difficulty and the lack of typical symptoms. The existing gold standard of diagnosing LM is to use positive cerebrospinal fluid (CSF) cytology, which consumes significantly more time to classify cells under a microscope.Objective: This study aims to establish a deep learning model to classify cancer cells in CSF, thus facilitating doctors to achieve an accurate and fast diagnosis of LM in an early stage.Method: The cerebrospinal fluid laboratory of Xijing Hospital provides 53,255 cells from 90 LM patients in the research. We used two deep convolutional neural networks (CNN) models to classify cells in the CSF. A five-way cell classification model (CNN1) consists of lymphocytes, monocytes, neutrophils, erythrocytes, and cancer cells. A four-way cancer cell classification model (CNN2) consists of lung cancer cells, gastric cancer cells, breast cancer cells, and pancreatic cancer cells. Here, the CNN models were constructed by Resnet-inception-V2. We evaluated the performance of the proposed models on two external datasets and compared them with the results from 42 doctors of various levels of experience in the human-machine tests. Furthermore, we develop a computer-aided diagnosis (CAD) software to generate cytology diagnosis reports in the research rapidly.Results: With respect to the validation set, the mean average precision (mAP) of CNN1 is over 95% and that of CNN2 is close to 80%. Hence, the proposed deep learning model effectively classifies cells in CSF to facilitate the screening of cancer cells. In the human-machine tests, the accuracy of CNN1 is similar to the results from experts, with higher accuracy than doctors in other levels. Moreover, the overall accuracy of CNN2 is 10% higher than that of experts, with a time consumption of only one-third of that consumed by an expert. Using the CAD software saves 90% working time of cytologists.Conclusion: A deep learning method has been developed to assist the LM diagnosis with high accuracy and low time consumption effectively. Thanks to labeled data and step-by-step training, our proposed method can successfully classify cancer cells in the CSF to assist LM diagnosis early. In addition, this unique research can predict cancer’s primary source of LM, which relies on cytomorphologic features without immunohistochemistry. Our results show that deep learning can be widely used in medical images to classify cerebrospinal fluid cells. For complex cancer classification tasks, the accuracy of the proposed method is significantly higher than that of specialist doctors, and its performance is better than that of junior doctors and interns. The application of CNNs and CAD software may ultimately aid in expediting the diagnosis and overcoming the shortage of experienced cytologists, thereby facilitating earlier treatment and improving the prognosis of LM.
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| 4. |
- Alimena, Juliette, et al.
(author)
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Searching for long-lived particles beyond the Standard Model at the Large Hadron Collider
- 2020
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In: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 47:9
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Journal article (peer-reviewed)abstract
- Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these long-lived particles (LLPs) can decay far from the interaction vertex of the primary proton-proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP signatures at the LHC is beneficial to ensure that possible avenues of the discovery of new physics are not overlooked. Here we report on the joint work of a community of theorists and experimentalists with the ATLAS, CMS, and LHCb experiments-as well as those working on dedicated experiments such as MoEDAL, milliQan, MATHUSLA, CODEX-b, and FASER-to survey the current state of LLP searches at the LHC, and to chart a path for the development of LLP searches into the future, both in the upcoming Run 3 and at the high-luminosity LHC. The work is organized around the current and future potential capabilities of LHC experiments to generally discover new LLPs, and takes a signature-based approach to surveying classes of models that give rise to LLPs rather than emphasizing any particular theory motivation. We develop a set of simplified models; assess the coverage of current searches; document known, often unexpected backgrounds; explore the capabilities of proposed detector upgrades; provide recommendations for the presentation of search results; and look towards the newest frontiers, namely high-multiplicity 'dark showers', highlighting opportunities for expanding the LHC reach for these signals.
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| 5. |
- Liu, Qiao, et al.
(author)
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Enhanced ionic conductivity and interface stability of hybrid solid-state polymer electrolyte for rechargeable lithium metal batteries
- 2019
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In: Energy Storage Materials. - : Elsevier BV. - 2405-8297. ; 23, s. 105-111
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Journal article (peer-reviewed)abstract
- Compared to conventional organic liquid electrolyte, solid-state polymer electrolytes are extensively considered as an alternative candidate for next generation high-energy batteries because of their high safety, non-leakage and electrochemical stability with the metallic lithium (Li) anode. However, solid-state polymer electrolytes generally show low ionic conductivity and high interfacial impedance to electrodes. Here we report a hybrid solid-state electrolyte, presenting an ultra-high ionic conductivity of 3.27 mS cm −1 at room temperature, a wide electrochemical stability window of 4.9 V, and non-flammability. This electrolyte consists of a polymer blend matrix (polyethylene oxide and poly (vinylidene fluoride-co-hexafluoropropylene)), Li + conductive ceramic filler (Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 ) and a solvate ionic liquid (LiFSI in tetra ethylene glycol dimethyl ether, 1:1 in molar ratio) as plasticizer. The introduction of the solvate ionic liquid to the solid-state electrolyte not only improves its ionic conductivity but also remarkably enhances the stability of the interface with Li anode. When applied in Li metal batteries, a Li|Li symmetric cell can operate stably over 800 h with a minimal polarization of 25 mV and a full Li|LiFePO 4 cell delivers a high specific capacity of 158 mAh g −1 after 100 cycles at room temperature.
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| 6. |
- Wang, Kai, et al.
(author)
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A one-carbon chemicals conversion strategy to produce precursor of biofuels with Saccharomyces cerevisiae
- 2023
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In: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 208, s. 331-340
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Journal article (peer-reviewed)abstract
- Utilization of one-carbon chemicals such as CO2, formate, and methanol by microorganisms can enable the sustainable production of fuels and chemicals. However, the low conversion efficiency of these chemicals by microorganisms is a major challenge. To address this, we designed a one-carbon strategy that can utilize CO2 and its derivative formate. Here, a platform yeast strain with improved formate utilization and NAD(P)H production was constructed and evaluated for its ability to produce free fatty acids (FFAs). Based on 13C-marked analysis, the one-carbon assimilation efficiency of the platform strain reached 11.24%. Through continuous optimization, under conditions of glucose feeding the formate utilization rate of the final strain reached 0.48 g/L/h, with the final titer of FFAs reached 10.1 g/L, which represented improvements of 21.8 times and 33.7 times, respectively. As such, the produced FFAs can be easily transformed into biodiesel by combining them with downstream technologies in future research.
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| 7. |
- Wang, Zhenqian, et al.
(author)
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Northward migration of the East Asian summer monsoon northern boundary during the twenty-first century
- 2022
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12
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Journal article (peer-reviewed)abstract
- The northern fringe area of the East Asian summer monsoon (EASM) between arid and semiarid regions is a fragile eco-environment zone and ecological transition zone, and it is highly sensitive to climate change. Predicting the future migration of the northern boundary of the EASM is important for understanding future East Asian climate change and formulating of decisions on ecological protection and economic development in arid and semiarid regions. The reanalysis dataset and simulations of 23 models from the Coupled Models Intercomparison Project Phase 6 (CMIP6) were used to investigate the response of the boundary of the ESAM to the global warming. The multi-model ensemble showed a northwestward migration of the EASM northern boundary during the near-term (2020–2060) and late-term (2061–2099) of the twenty-first century under various Shared Socioeconomic Pathways (SSPs). The northern boundary migrated northwestward by 23–28 and 74–76 km in the near-term and late-term respectively, under SSP1-2.6, 2-4.5 and 3-7.0 and by ~ 44 km and ~ 107 km respectively during the near-term and late-term under SSP5-8.5. During the twenty-first century, under various SSPs, the surface of the East Asian subcontinent warmed more than the ocean, thereby increasing the contrast of near-surface temperature and sea level pressure in summer between the East Asian subcontinent and the surrounding oceans. In turn, the intensified land–sea thermal contrast reinforced the EASM meridional circulation and thus transported more moisture from the Indian Ocean into northern China. Additionally, a poleward migration and weakening of the East Asian subtropical westerly jet would also favor an increase in precipitation, eventually caused a northwestward migration of the EASM northern boundary. The results suggest that the arid and semiarid ecotone will become wetter, which could dramatically improve the eco-environment in the future.
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| 8. |
- Xiong, Shizhao, 1985, et al.
(author)
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Design of a Multifunctional Interlayer for NASCION-Based Solid-State Li Metal Batteries
- 2020
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In: Advanced Functional Materials. - : Wiley. - 1616-3028 .- 1616-301X. ; 30:22
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Journal article (peer-reviewed)abstract
- NASCION-type Li conductors have great potential to bring high capacity solid-state batteries to realization, related to its properties such as high ionic conductivity, stability under ambient conditions, wide electrochemical stability window, and inexpensive production. However, their chemical and thermal instability toward metallic lithium (Li) has severely hindered attempts to utilize Li as anode material in NASCION-based battery systems. In this work, it is shown how a tailored multifunctional interlayer between the solid electrolyte and Li anode can successfully address the interfacial issues. This interlayer is designed by creating a quasi-solid-state paste in which the functionalities of LAGP (Li1.5Al0.5Ge1.5(PO4)3) nanoparticles and an ionic liquid (IL) electrolyte are combined. In a solid-sate cell, the LAGP-IL interlayer separates the Li metal from bulk LAGP and creates a chemically stable interface with low resistance (≈5 Ω cm2) and efficiently prevents thermal runaway at elevated temperatures (300 °C). Solid-state cells designed with the interlayer can be operated at high current densities, 1 mA cm−2, and enable high rate capability with high safety. Here developed strategy provides a generic path to design interlayers for solid-state Li metal batteries.
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| 9. |
- Zhao, Wengao, et al.
(author)
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Quantifying Degradation Parameters of Single-Crystalline Ni-Rich Cathodes in Lithium-Ion Batteries
- 2023
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In: Angewandte Chemie - International Edition. - 1433-7851 .- 1521-3773. ; 62:32
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Journal article (peer-reviewed)abstract
- Single-crystal LiNixCoyMnzO2 (SC-NCM, x+y+z=1) cathodes are renowned for their high structural stability and reduced accumulation of adverse side products during long-term cycling. While advances have been made using SC-NCM cathode materials, careful studies of cathode degradation mechanisms are scarce. Herein, we employed quasi single-crystalline LiNi0.65Co0.15Mn0.20O2 (SC-NCM65) to test the relationship between cycling performance and material degradation for different charge cutoff potentials. The Li/SC-NCM65 cells showed >77 % capacity retention below 4.6 V vs. Li+/Li after 400 cycles and revealed a significant decay to 56 % for 4.7 V cutoff. We demonstrate that the SC-NCM65 degradation is due to accumulation of rock-salt (NiO) species at the particle surface rather than intragranular cracking or side reactions with the electrolyte. The NiO-type layer formation is also responsible for the strongly increased impedance and transition-metal dissolution. Notably, the capacity loss is found to have a linear relationship with the thickness of the rock-salt surface layer. Density functional theory and COMSOL Multiphysics modeling analysis further indicate that the charge-transfer kinetics is decisive, as the lower lithium diffusivity of the NiO phase hinders charge transport from the surface to the bulk.
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| 10. |
- Chen, Yaqi, et al.
(author)
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Insight into the Extreme Side Reaction between LiNi0.5Co0.2Mn0.3O2 and Li1.3Al0.3Ti1.7(PO4)3 during Cosintering for All-Solid-State Batteries
- 2023
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In: Chemistry of Materials. - 1520-5002 .- 0897-4756. ; 35:22, s. 9647-9656
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Journal article (peer-reviewed)abstract
- All-solid-sate batteries (ASSBs) with a NASICON-type solid-state electrolyte (SSE) of Li1.3Al0.3Ti1.7(PO4)3 (LATP) can be accepted as a promising candidate to significantly improve safety and energy density due to their high oxidation potential and high ionic conductivity. However, thermodynamic instability between the cathode and LATP is scarcely investigated during cosintering preparation for the integrated configuration of ASSBs. Herein, the structural compatibility between commercially layered LiNi0.5Co0.2Mn0.3O2 (NCM523) and LATP SSE was systematically investigated by cosintering at 600 °C. It is noticeable that an extreme side reaction between Li from NCM523 and phosphate from LATP happens during its cosintering process, leading to a severe phase transition from a layered to a spinel structure with high Li/Ni mixing. Consequently, the capacity of NCM523 is lost during the preparation of the NCM523-LATP composite cathode. Based on this, we suggested that the interface modification of the NCM523/LATP interface is valued significantly to inhibit this extreme side reaction, quickening the application of LATP-based ASSBs.
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| 11. |
- Chen, Yaqi, et al.
(author)
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Two Birds with One Stone: Using Indium Oxide Surficial Modification to Tune Inner Helmholtz Plane and Regulate Nucleation for Dendrite-free Lithium Anode
- 2022
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In: Small Methods. - : Wiley. - 2366-9608. ; 6:5
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Journal article (peer-reviewed)abstract
- Lithium metal has been considered as the most promising anode material due to its distinguished specific capacity of 3860 mAh g–1 and the lowest reduction potential of -3.04 V versus the Standard Hydrogen Electrode. However, the practicalization of Li-metal batteries (LMBs) is still challenged by the dendritic growth of Li during cycling, which is governed by the surface properties of the electrodepositing substrate. Herein, a surface modification with indium oxide on the copper current collector via magnetron sputtering, which can be spontaneously lithiated to form a composite of lithium indium oxide and Li-In alloy, is proposed. Thus, the growth of Li dendrites is effectively suppressed via regulating the inner Helmholtz plane modified with LiInO2 to foster the desolvation of Li-ion and induce the nucleation of Li-metal in two-dimensions through electro-crystallization with Li-In alloy. Using the In2O3 modification, the Li-metal anode exhibits outstanding cyclic stability, and LMBs with lithium cobalt oxide cathode present excellent capacity retention (above 80% over 600 cycles). Enlightening, the scalable magnetron sputtering method reported here paves a novel way to accelerate the practical application of the Li anode in LMBs to pursue higher energy density.
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| 12. |
- Chen, Yangyang, et al.
(author)
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Wood-derived scaffolds decorating with nickel cobalt phosphate nanosheets and carbon nanotubes used as monolithic electrodes for assembling high-performance asymmetric supercapacitor
- 2023
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In: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 454
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Journal article (peer-reviewed)abstract
- Lightweight carbonized wood (CW) loaded with pseudocapacitive materials has demonstrated excellent energy density. However, the direct loading of active materials usually results in poor rate performance and cycling stability. Herein, we fabricated a CW electrode with high loading of active materials and conductivity through chemical vapor deposition (CVD) and electrodeposition to sequentially incorporate carbon nanotubes (CNTs) and nickel-cobalt phosphate (NiCo-P) nanosheets. This integrated NiCo-P/CNT/CW electrode exhibited a promising areal capacitance of 11.2F cm-2 at a current density of 10 mA cm-2, and a notable capacitance retention rate of 86.6 % at 60 mA cm-2. The asymmetric supercapacitor (ASC) device assembled with the prepared electrode as anode and the self-activated carbonized wood (SCW) electrode as cathode delivers outstanding energy density of 5.74 mWh cm-3 (12.1 Wh kg -1) at power density of 18.75 mW cm-3 (39.5 W kg -1) while maintaining a high capacitance retention of 92.4 % after 10,000 charge-discharge cycles. This work provides an advanced approach for constructing supercapacitors with remarkable energy density and rate performance from the natural wood derived electrodes.
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| 13. |
- Dhakal, Gyanendra, et al.
(author)
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Observation of anisotropic Dirac cones in the topological material Ti2Te2P
- 2022
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In: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 106:12
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Journal article (peer-reviewed)abstract
- Anisotropic bulk Dirac (or Weyl) cones in three-dimensional systems have recently gained intense research interest as they are examples of materials with tilted Dirac (or Weyl) cones indicating the violation of Lorentz invariance. In contrast, the studies on anisotropic surface Dirac cones in topological materials which contribute to anisotropic carrier mobility have been limited. By employing angle-resolved photoemission spectroscopy and first-principles calculations, we reveal the anisotropic surface Dirac dispersion in a tetradymite material Ti2Te2P on the (001) plane of the Brillouin zone. We observe quasielliptical Fermi pockets at the (M) over bar point of the Brillouin zone forming the anisotropic surface Dirac cones. Our calculations of the Z(2) indices confirm that the system is topologically nontrivial with multiple topological phases in the same material. In addition, the observed nodal-line-like feature formed by bulk bands makes this system topologically rich.
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| 14. |
- Jiang, Linfeng, et al.
(author)
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RMAU-Net : Residual Multi-Scale Attention U-Net For liver and tumor segmentation in CT images
- 2023
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In: Computers in Biology and Medicine. - : Elsevier BV. - 0010-4825 .- 1879-0534. ; 158
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Journal article (peer-reviewed)abstract
- Liver cancer is one of the leading causes of cancer-related deaths worldwide. Automatic liver and tumor segmentation are of great value in clinical practice as they can reduce surgeons' workload and increase the probability of success in surgery. Liver and tumor segmentation is a challenging task because of the different sizes, shapes, blurred boundaries of livers and lesions, and low-intensity contrast between organs within patients. To address the problem of fuzzy livers and small tumors, we propose a novel Residual Multi-scale Attention U-Net (RMAU-Net) for liver and tumor segmentation by introducing two modules, i.e., Res-SE-Block and MAB. The Res-SE-Block can mitigate the problem of gradient disappearance by residual connection and enhance the quality of representations by explicitly modeling the interdependencies and feature recalibration between the channels of features. The MAB can exploit rich multi-scale feature information and capture inter -channel and inter-spatial relationships of features simultaneously. In addition, a hybrid loss function, that combines focal loss and dice loss, is designed to improve segmentation accuracy and speed up convergence. We evaluated the proposed method on two publicly available datasets, i.e., LiTS and 3D-IRCADb. Our proposed method achieved better performance than the other state-of-the-art methods, with dice scores of 0.9552 and 0.9697 for LiTS and 3D-IRCABb liver segmentation, and dice scores of 0.7616 and 0.8307 for LiTS and 3D-IRCABb liver tumor segmentation.
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| 15. |
- Jiao, Xingxing, et al.
(author)
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Crumpled Nitrogen-Doped Graphene-Wrapped Phosphorus Composite as a Promising Anode for Lithium-Ion Batteries
- 2019
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In: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 11:34, s. 30858-30864
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Journal article (peer-reviewed)abstract
- Red phosphorus (P) has recently gained wide attention because of the high theoretical capacity of 2596 mA h/g, which has been regarded as promising anode material for lithium-ion batteries (LIBs). However, the actual application of red P in LIBs is hampered by the huge expansion of volume and low electronic conductivity. Herein, we design a kind of red phosphorus/crumpled nitrogen-doped graphene (P/CNG) nanocomposites with high capacity density and great rate performance as anode material for LIBs. This anode material was rationally fabricated through the scalable ball-milling method. The nanocomposite structure of P/CNG improves the electron conductivity and alleviates volume change of raw red P because of the three-dimension (3D) framework, massive defects and active sites of CNG sheets. As expected, the P/CNG composite shows excellent electrochemical performances, including high capacity (2522.6 mA h/g at 130 mA/g), remarkable rate capability (1340.5 mA h/g at 3900 mA/g), and great cyclability (1470.1 mA h/g at 1300 mA/g for 300 cycles). This work may provide a broad prospect for a great rate performance of P-based anode material for LIBs.
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| 16. |
- Jiao, Xingxing, et al.
(author)
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Electro-chemo-mechanical failure of solid-state electrolyte caused from intergranular or transgranular damage propagation in polycrystalline aggregates
- 2024
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In: Acta Materialia. - 1359-6454. ; 265
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Journal article (peer-reviewed)abstract
- Electro-chemo-mechanical failure of solid-state electrolytes (SEs) caused by the internal growth of lithium dendrites significantly impedes the application of solid-state batteries under high applied current density. The grain boundary is usually the key to the mechanical properties of polycrystalline ceramic SEs. Here, strength and width of grain boundary in SEs that are exampled by garnet-type Li7La3Zr2O12 are evaluated under the deposition of lithium by visualizing the stress field, damage accumulation and crack propagation. The enhancement of grain boundary strength triggers a dramatic increase stress when the ratio of tensile strength between grain boundary and grain (λ) is lower than 0.9. With the variation of λ, three damage processes are revealed as intergranular-damage, inter/transgranular-damage and transgranular-damage, leading to different propagation of cracks and the transformation of intergranular failure to transgranular failure. Furthermore, the width of the grain boundary is found to induce more transgranular-damage with its widening. A critical value of grain boundary width for the formation of displacement is obtained under various strengths, as δ = 21 nm for λ = 0.2, δ = 25 nm for λ = 0.5 and δ = 31 nm for λ = 0.9. The findings in this work indicate the coupling effect of grain boundary width and strength on the failure of SEs, providing an insightful perspective for the future design of solid-state batteries.
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| 17. |
- Jiao, Xingxing, et al.
(author)
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Grain size and grain boundary strength: Dominative role in electro-chemo-mechanical failure of polycrystalline solid-state electrolytes
- 2024
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In: Energy Storage Materials. - 2405-8297. ; 65
-
Journal article (peer-reviewed)abstract
- Solid-state batteries with lithium metal anode have been accepted extensively as the competitive option to fulfill the upping requirement for safe and efficient energy devices. Nevertheless, its wide-ranging application has been impeded by the failure of solid-state electrolyte (SSE) induced by development of lithium (Li) filament. Based on the nature of polycrystalline ceramic SSE with varying grain size and boundary strength, the constitutive equation coupled with electrochemical kinetics was applied to picture the propagation of damage and corresponding disintegration caused by the development of Li filament. Based on the results, we found that the stress generated along with the growth of Li filament spreads away via the opening and sliding of grain boundary. Thus, damage occurs along grain boundaries, of which propagation behavior and damage level are controlled by grain size. Especially, over-refinement and under-refinement of grains of SSE can cause flocculent damage with inordinate damage degree and accelerate the failure time of SSE, respectively. On the other hand, the failure time is powerfully prolongated through strengthening the grain boundary of SSE. Eventually, grain size of 0.2 μm and tensile strength of grain boundary of 0.8-time-of-grain are posted as the threshold to realize the postponed failure of NASICON-based SSE. Inspiringly, electro-chemo-mechanical model in this contribution is generally applicable to other type of ceramic SSE to reveal the failure process and provide the design guideline, fostering the improvement of solid-state batteries.
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| 18. |
- Jiao, Xingxing, et al.
(author)
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Highly Energy-Dissipative, Fast Self-Healing Binder for Stable Si Anode in Lithium-Ion Batteries
- 2021
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In: Advanced Functional Materials. - : Wiley. - 1616-3028 .- 1616-301X. ; 31:3
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Journal article (peer-reviewed)abstract
- A double-wrapped binder has been rationally designed with high Young's modulus polyacrylic acid (PAA) inside and low Young's modulus bifunctional polyurethane (BFPU) outside to address the large inner stress of silicon anode with drastic volume changes during cycling. Harnessing the "hard to soft" gradient distribution strategy, the rigid PAA acts as a protective layer to dissipate the inner stress first during lithiation, while the elastic binder BFPU serves as a buffer layer to disperse residual stress, and thus avoids structural damage of rigid PAA. Moreover, the introduction of BFPU with fast self-healing ability can dynamically recover the microcracks arising from large stress, further ensuring the integrity of silicon anode. This multifunctional binder with smart design of double-wrapped structure provides enlightenment on enlarging the cycling life of high-energy-density lithium-ion batteries that suffer enormous volume change during the cycling process.
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| 19. |
- Jiao, Xingxing, et al.
(author)
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Insight of electro-chemo-mechanical process inside integrated configuration of composite cathode for solid-state batteries
- 2023
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In: Energy Storage Materials. - 2405-8297. ; 61
-
Journal article (peer-reviewed)abstract
- The complicated electro-chemo-mechanical process that occurs inside the composite cathode for solid-state batteries (SSBs), is of first importance to be insighted for the development of SSBs to seek higher energy density. Herein, exampled with layered transition-metal oxide of LiNixCoyMn1-x-yO2 (NCM), an electro-chemo-mechanical model containing electrochemical kinetics, finite-strain constitutive model and cohesive zone model was built to uncover the impact of ionic conductivity and Young's modulus (E) of solid-state electrolyte (SE) on the electro-chemo-mechanical process inside composite cathode and the intergranular failure of single cathode particle. The intergranular failure of NCM particles is powerfully determined by the Young's modulus of SE and the primary particle size, which is postponed by the coarse-primary NCM with soft SE of E=∼2 GPa. Compared with Young's modulus, increasing the ionic conductivity can uniform the distribution of both Li-ion and stress in the whole composite NCM cathode, realizing improved electrochemical performance with larger normalized capacity and lower the interfacial impendence. Hence, high-adequate ionic conductivity of 5 × 10−4 S cm−1 and soft mechanical property of E=∼2 GPa can be proposed as the guideline of SE for great electrochemical performance with prolongated lifespan of composite NCM cathode, paving an avenue to foster the application of SSBs.
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| 20. |
- Jiao, Xingxing, et al.
(author)
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Morphology evolution of electrodeposited lithium on metal substrates
- 2023
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In: Energy Storage Materials. - 2405-8297. ; 61
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Journal article (peer-reviewed)abstract
- Lithium (Li) metal is deemed to be the high-energy-density anode material for next generation batteries, but its practical application is impeded by the uneven electrodeposition during charge of battery, which leads to the low Coulombic efficiency and potential safety issue. Here, multiscale modeling is fabricated to understand the morphology evolution of Li during electrodeposition process, from the self-diffusion of Li adatoms on electrode surface, to the nucleation process, and to the formation of Li microstructures, revealing the correlation between final morphology and deposition substrates. Energy batteries and self-diffusion of Li adatom on various substrates (lithium, copper, nickel, magnesium, and silver) result in the different nucleation size, which is calculated by kinetic Monte Carlo simulation based on classical nucleation theory. Formation of Li substructures that are grown from Li nuclei, is revealed by phase field modeling coupled with cellular automaton method. Our results show that larger Li nuclei is obtained under faster self-diffusion of Li adatom, leading to the low aspect ratio of Li substructures and the subsequent morphology evolution of electrodeposited Li. Furthermore, the electrodeposition of Li is strongly regulated by the selection of substrates, giving the practical guideline of anode design in rechargeable Li metal batteries. It is worthy to mention that this method to investigate the electro-crystallization process involving nucleation and growth can be transplanted to the other metallic anode, such as sodium, potassium, zinc, magnesium, calcium and the like.
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| 21. |
- Jiao, Xingxing, et al.
(author)
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Multi-Physical Field Simulation: A Powerful Tool for Accelerating Exploration of High-Energy-Density Rechargeable Lithium Batteries
- 2023
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In: Advanced Energy Materials. - 1614-6840 .- 1614-6832. ; In Press
-
Research review (peer-reviewed)abstract
- To meet the booming demand of high-energy-density battery systems for modern power applications, various prototypes of rechargeable batteries, especially lithium metal batteries with ultrahigh theoretical capacity, have been intensively explored, which are intimated with new chemistries, novel materials and rationally designed configurations. What happens inside the batteries is associated with the interaction of multi-physical field, rather than the result of the evolution of a single physical field, such as concentration field, electric field, stress field, morphological evolution, etc. In this review, multi-physical field simulation with a relatively wide length and timescale is focused as formidable tool to deepen the insight of electrodeposition mechanism of Li metal and the electro-chemo-mechanical failure of solid-state electrolytes based on Butler-Volmer electrochemical kinetics and solid mechanics, which can promote the future development of state-of-the-art Li metal batteries with satisfied energy density as well as lifespan.
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| 22. |
- Jiao, Xingxing, et al.
(author)
-
Viability of all-solid-state lithium metal battery coupled with oxide solid-state electrolyte and high-capacity cathode
- 2024
-
In: Journal of Energy Chemistry. - 2095-4956. ; 91, s. 122-131
-
Journal article (peer-reviewed)abstract
- Owing to the utilization of lithium metal as anode with the ultrahigh theoretical capacity density of 3860 mA h g−1 and oxide-based ceramic solid-state electrolytes (SE), e.g., garnet-type Li7La3Zr2O12 (LLZO), all-state-state lithium metal batteries (ASLMBs) have been widely accepted as the promising alternatives for providing the satisfactory energy density and safety. However, its applications are still challenged by plenty of technical and scientific issues. In this contribution, the co-sintering temperature at 500 °C is proved as a compromise method to fabricate the composite cathode with structural integrity and declined capacity fading of LiNi0.5Co0.2Mn0.3O2 (NCM). On the other hand, it tends to form weaker grain boundary (GB) inside polycrystalline LLZO at inadequate sintering temperature for LLZO, which can induce the intergranular failure of SE during the growth of Li filament inside the unavoidable defect on the interface of SE. Therefore, increasing the strength of GB, refining the grain to 0.4 μm, and precluding the interfacial defect are suggested to postpone the electro-chemo-mechanical failure of SE with weak GB. Moreover, the advanced sintering techniques to lower the co-sintering temperature for both NCM-LLZO composite cathode and LLZO SE can be posted out to realize the viability of state-of-the-art ASLMBs with higher energy density as well as the guaranteed safety.
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| 23. |
- Kang, Hyokyeong, et al.
(author)
-
Relaxation of Stress Propagation in Alloying-Type Sn Anodes for K-Ion Batteries
- 2024
-
In: Small Methods. - 2366-9608. ; 8:1
-
Journal article (peer-reviewed)abstract
- Alloying-type metallic tin is perceived as a potential anode material for K-ion batteries owing to its high theoretical capacity and reasonable working potential. However, pure Sn still face intractable issues of inferior K+ storage capability owing to the mechanical degradation of electrode against large volume changes and formation of intermediary insulating phases K4Sn9 and KSn during alloying reaction. Herein, the TiC/C–carbon nanotubes (CNTs) is prepared as an effective buffer matrix and composited with Sn particles (Sn–TiC/C–CNTs) through the high-energy ball-milling method. Owing to the conductive and rigid properties, the TiC/C–CNTs matrix enhances the electrical conductivity as well as mechanical integrity of Sn in the composite material and thus ultimately contributes to performance supremacy in terms of electrochemical K+ storage properties. During potassiation process, the TiC/C–CNTs matrix not only dissipates the internal stress toward random radial orientations within the Sn particle but also provides electrical pathways for the intermediate insulating phases; this tends to reduce microcracking and prevent considerable electrode degradation.
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| 24. |
- Lee, Suyeong, et al.
(author)
-
High-Energy and Long-Lifespan Potassium–Sulfur Batteries Enabled by Concentrated Electrolyte
- 2022
-
In: Advanced Functional Materials. - : Wiley. - 1616-3028 .- 1616-301X. ; 32:46
-
Journal article (peer-reviewed)abstract
- Potassium–sulfur (K–S) batteries are emerging as low-cost and high-capacity energy-storage technology. However, conventional K–S batteries suffer from two critical issues that have not yet been successfully resolved: the dissolution of potassium polysulfides (KPS) into the liquid electrolyte and the formation of K dendrites on the K metal anode, which lead to inadequate cycling efficiencies with a low reversible capacity. Herein, a high-capacity and long cycle-life K–S battery consisting of a highly concentrated electrolyte (HCE) (4.34 mol kg−1 potassium bis(fluorosulfonyl)imide in a 1,2-Dimethoxyethane) and a sulfurized polyacrylonitrile (SPAN) cathode is presented The application of a HCE efficiently suppresses the dendritic growth of K, as evidenced by operando optical imaging and phase field modeling, owing to the reduced K-ion depletion on the electrode surface and a uniform Faradaic current density over the K metal anode surface. Additionally, because S is covalently bonded to the C backbone of PAN in the SPAN structure, the SPAN cathode inhibits the dissolution of KPS. These features generate synergy that the proposed K–S battery can provide a practical areal capacity of 2.5 mAh cm−2 and unprecedented lifetimes with high Coulombic efficiencies over 700 cycles.
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| 25. |
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| 26. |
- Leimbach, David, 1992, et al.
(author)
-
The electron affinity of astatine
- 2020
-
In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11
-
Journal article (peer-reviewed)abstract
- One of the most important properties influencing the chemical behavior of an element is the electron affinity (EA). Among the remaining elements with unknown EA is astatine, where one of its isotopes, 211At, is remarkably well suited for targeted radionuclide therapy of cancer. With the At− anion being involved in many aspects of current astatine labeling protocols, the knowledge of the electron affinity of this element is of prime importance. Here we report the measured value of the EA of astatine to be 2.41578(7) eV. This result is compared to state-of-the-art relativistic quantum mechanical calculations that incorporate both the Breit and the quantum electrodynamics (QED) corrections and the electron–electron correlation effects on the highest level that can be currently achieved for many-electron systems. The developed technique of laser-photodetachment spectroscopy of radioisotopes opens the path for future EA measurements of other radioelements such as polonium, and eventually super-heavy elements.
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| 27. |
- Li, Shijia, et al.
(author)
-
Textured Na 2 V 6 O 16 ·3H 2 O Cathode Tuned via Crystal Engineering Endows Aqueous Zn-Ion Batteries with High Rate Capability and Adequate Lifespan
- 2022
-
In: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 7:11, s. 3770-3779
-
Journal article (peer-reviewed)abstract
- Aqueous zinc-ion batteries (ZIBs) play a vital role in large-scale energy storage for smart grids due to their environmental friendliness, safety, and low cost. Unfortunately, the application of ZIBs has been challenged by the relatively low capacity of cathode materials, especially at higher rates, which originates from the sluggish diffusion of Zn ions. Herein, a crystal engineering strategy is explored for using bernesite, Na2V6O16·3H2O (NVO), for regulating the diffusion-preferable texture, which was beneficial for fostering Zn ions' diffusion and thus guaranteeing a uniform concentration inside the cathode. An enlarged capacity at a higher rate was obtained, delivering a capacity of 156.9 mAh g-1 at the ultra-high current density of 20 A g-1, of which 140.6 mAh g-1 remained after 5000 cycles. The use of crystal engineering to regulate the texture of cathode materials paves the way to boost the application of NVO in aqueous ZIBs, which could be translated to design state-of-the-art cathodes for other battery systems.
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| 28. |
- Liu, Yangyang, et al.
(author)
-
Discriminating the impacts of vegetation greening and climate change on the changes in evapotranspiration and transpiration fraction over the Yellow River Basin
- 2023
-
In: Science of the Total Environment. - 0048-9697 .- 1879-1026. ; 904
-
Journal article (peer-reviewed)abstract
- Evapotranspiration (ET) is a vital parameter in terrestrial water-energy cycles. The transpiration fraction (TF) is defined as the ratio of transpiration (T) to evapotranspiration (ET), representing the contribution rate of vegetation transpiration to ecosystem ET. Quantifying the relative contributions of vegetation and climate change on the ET and TF dynamic is of great significance to better understand the water budget between the land and atmosphere. Here, we chose Yellow River Basin (YRB) as the study area and analyzed the spatiotemporal changes of ET, T, and TF from 1982 to 2015 using the Priestley-Taylor Jet Propulsion Laboratory (PT-JPL) model. Meanwhile, the relative contributions of vegetation and climate change to ET, T and TF change were quantified. Model evaluation showed that the PT-JPL model performs well in the simulation of ET and T. During 1982–2015, the average annual ET, T, and TF increased at a rate of 3.20 mm/a, 0.77 mm/a and 0.003/a over the YRB during 1982–2015, respectively. The regions with significant increases in ET, T and TF almost covered the whole study area except for the upper reaches of the YRB. Vegetation greening was the main factor for the increase of ET and TF in the YRB and enhanced ET and TF at a rate of 0.72 mm/a and 0.57/a, respectively, which mainly observed in the entire Loess Plateau region (over 50 % of the study area). Precipitation (PRE) was also the dominated factor contributing to the increase in ET and TF, and temperature (TEM) showed a positive correlation with the changes in ET and TF in the most areas of YRB, which jointly dominated ET changes in the upper reaches of the YRB and TF changes in the southern part of the basin. Except for the total effects, leaf area index (LAI) also indirectly promoted ET changes by affecting PRE, TEM and relative humidity (RH). While wind speed (WS) and radiation (RAD) had a relatively weak regulatory effect on the changes in ET and TF. These findings were helpful for regional water resources management and formulating water resources-sustainable vegetation restoration strategies for local government.
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| 29. |
- Liu, Yangyang, et al.
(author)
-
Electro-Chemo-Mechanical Modeling of Artificial Solid Electrolyte Interphase to Enable Uniform Electrodeposition of Lithium Metal Anodes
- 2022
-
In: Advanced Energy Materials. - : Wiley. - 1614-6840 .- 1614-6832. ; 12:9
-
Journal article (peer-reviewed)abstract
- Nonuniform electrodeposition of lithium during charging processes is the key issue hindering development of rechargeable Li metal batteries. This deposition process is largely controlled by the solid electrolyte interphase (SEI) on the metal surface and the design of artificial SEIs is an essential pathway to regulate electrodeposition of Li. In this work, an electro-chemo-mechanical model is built and implemented in a phase-field modelling to understand the correlation between the physical properties of artificial SEIs and deposition of Li. The results show that improving ionic conductivity of the SEI above a critical level can mitigate stress concentration and preferred deposition of Li. In addition, the mechanical strength of the SEI is found to also mitigate non-uniform deposition and influence electrochemical kinetics, with a Young's modulus around 4.0 GPa being a threshold value for even deposition of Li. By comparison of the results to experimental results for artificial SEIs it is clear that the most important direction for future work is to improve the ionic conductivity without compromising mechanical strength. In addition, the findings and methodology presented here not only provide detailed guidelines for design of artificial SEI on Li-metal anodes but also pave the way to explore strategies for regulating deposition of other metal anodes.
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| 30. |
- Liu, Yangyang, et al.
(author)
-
Insight into the Critical Role of Exchange Current Density on Electrodeposition Behavior of Lithium Metal
- 2021
-
In: Advanced Science. - : Wiley. - 2198-3844 .- 2198-3844. ; 8:5
-
Journal article (peer-reviewed)abstract
- Due to an ultrahigh theoretical specific capacity of 3860 mAh g−1, lithium (Li) is regarded as the ultimate anode for high-energy-density batteries. However, the practical application of Li metal anode is hindered by safety concerns and low Coulombic efficiency both of which are resulted fromunavoidable dendrite growth during electrodeposition. This study focuses on a critical parameter for electrodeposition, the exchange current density, which has attracted only little attention in research on Li metal batteries. A phase-field model is presented to show the effect of exchange current density on electrodeposition behavior of Li. The results show that a uniform distribution of cathodic current density, hence uniform electrodeposition, on electrode is obtained with lower exchange current density. Furthermore, it is demonstrated that lower exchange current density contributes to form a larger critical radius of nucleation in the initial electrocrystallization that results in a dense deposition of Li, which is a foundation for improved Coulombic efficiency and dendrite-free morphology. The findings not only pave the way to practical rechargeable Li metal batteries but can also be translated to the design of stable metal anodes, e.g., for sodium (Na), magnesium (Mg), and zinc (Zn) batteries.
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| 31. |
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| 32. |
- Liu, Yangyang, et al.
(author)
-
Promoted rate and cycling capability of Li–S batteries enabled by targeted selection of co-solvent for the electrolyte
- 2020
-
In: Energy Storage Materials. - : Elsevier BV. - 2405-8297. ; 25, s. 131-136
-
Journal article (peer-reviewed)abstract
- Lithium sulfur (Li–S) batteries are considered as promising candidates for high-energy-density battery systems owing to the high theoretical capacity of sulfur (1675 mAh g−1) and low cost of raw materials. However, their practical application is hampered by low rate capability and rapid degradation of capacity, arising from the passivation of the cathode by lithium sulfides (Li2S2/Li2S) deposited during discharge and low interfacial stability of the Li anode. Herein, we report on a comprehensive strategy to select co-solvent to the electrolyte to regulate the deposition of lithium sulfides during charge-discharge process. We show that addition of a co-solvent with high solubility, and strong interaction with Li2S to a conventional electrolyte effectively mitigates the formation of a passivating layer on the sulfur cathode and dramatically improves the interfacial stability of the Li anode. We demonstrate that Sulfolane (SL) has these properties and that a Li–S cell with an electrolyte containing 6 vol% SL exhibits outstanding cyclic performance (0.083% decay per cycle) and rate capability (capacity density of 765 mAh g−1 at rate of 1.0C). Thus, we provide a facile strategy for the selection of co-solvent for improved performance of Li–S batteries, realizing their practical application for high-energy-density battery systems.
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| 33. |
- Liu, Yangyang, et al.
(author)
-
Role of Interfacial Defects on Electro–Chemo–Mechanical Failure of Solid-State Electrolyte
- 2023
-
In: Advanced Materials. - 0935-9648 .- 1521-4095. ; 35:24
-
Journal article (peer-reviewed)abstract
- High-stress field generated by electroplating of lithium (Li) in pre-existing defects is the main reason for mechanical failure of solid-state electrolyte because it drives crack propagation in electrolyte, followed by Li filament growth inside and even internal short-circuit if the filament reaches another electrode. To understand the role of interfacial defects on mechanical failure of solid-state electrolyte, an electro–chemo–mechanical model is built to visualize distribution of stress, relative damage, and crack formation during electrochemical plating of Li in defects. Geometry of interfacial defect is found as dominating factor for concentration of local stress field while semi-sphere defect delivers less accumulation of damage at initial stage and the longest failure time for disintegration of electrolyte. Aspect ratio, as a key geometric parameter of defect, is investigated to reveal its impact on failure of electrolyte. Pyramidic defect with low aspect ratio of 0.2–0.5 shows branched region of damage near interface, probably causing surface pulverization of solid-state electrolyte, whereas high aspect ratio over 3.0 will trigger accumulation of damage in bulk electrolyte. The correction between interfacial defect and electro–chemo–mechanical failure of solid-state electrolyte is expected to provide insightful guidelines for interface design in high-power-density solid-state Li metal batteries.
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| 34. |
- Liu, Yangyang, et al.
(author)
-
Stable Li metal anode by crystallographically oriented plating through in-situ surface doping
- 2020
-
In: Science China Materials. - : Springer Science and Business Media LLC. - 2199-4501 .- 2095-8226. ; 63:6, s. 1036-1045
-
Journal article (peer-reviewed)abstract
- Lithium (Li) metal is regarded as the holy grail anode material for high-energy-density batteries owing to its ultrahigh theoretical specific capacity. However, its practical application is severely hindered by the high reactivity of metallic Li against the commonly used electrolytes and uncontrolled growth of mossy/dendritic Li. Different from widely-used approaches of optimization of the electrolyte and/or interfacial engineering, here, we report a strategy of in-situ cerium (Ce) doping of Li metal to promote the preferential plating along the [200] direction and remarkably decreased surface energy of metallic Li. The in-situ Ce-doped Li shows a significantly reduced reactivity towards a standard electrolyte and, uniform and dendrite-free morphology after plating/stripping, as demonstrated by spectroscopic, morphological and electrochemical characterizations. In symmetric half cells, the in-situ Ce-doped Li shows a low corrosion current density against the electrolyte and drastically improved cycling even at a lean electrolyte condition. Furthermore, we show that the stable Li LiCoO2 full cells with improved coulombic efficiency and cycle life are also achieved using the Ce-doped Li metal anode. This work provides an inspiring approach to bring Li metal towards practical application in high energy-density batteries.
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| 35. |
- Oh, Gwangeon, et al.
(author)
-
Stabilizing Layered-Type K 0.4 V 2 O 5 Cathode by K Site Substitution with Strontium for K-Ion Batteries
- 2024
-
In: Advanced Functional Materials. - 1616-3028 .- 1616-301X. ; In Press
-
Journal article (peer-reviewed)abstract
- Developing suitable cathodes with high capacity and high power is challenging for K-ion batteries. Herein, electrochemical K-ion storage properties of the layered-type K0.4V2O5 (KVO) cathode by incorporating divalent strontium ions (Sr2+) into its crystal structure are enhanced. Divalent strontium ions (1.18 Å) are preferentially incorporated into the octahedrally coordinated K (1.38 Å) layers due to the similar ionic size compared to V4+ (0.58 Å). The introduction of 3 mmol of Sr ions in the KVO crystal improves electrical conductivity and reduces K-ion diffusion energy barriers. In addition, the strong Sr2+ and O2− interaction acts as a structural pillar, suppressing irreversible phase transition during charge–discharge process. Multi-physics simulations clearly confirm that the K0.34Sr0.03V2O5 (KS3VO) cathode exhibits a more uniform K-ion distribution and enhanced reactions of K-ions compared to the KVO cathode at various depths of discharge. As a result, the KS3VO cathode demonstrates improved reversible capacity, cycling stability, and power capability over the KVO cathode in a K-ion cell. Synchrotron X-ray analysis reveals how Sr substitution enhances the electrochemical K-ion storage properties of the KS3VO cathode. In addition, the KS3VO cathode exhibits superior thermal stability and cycling stability in a full cell coupled with a hard carbon anode compared to the KVO cathode.
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| 36. |
- Park, Jimin, et al.
(author)
-
A Dual-Functional Electrolyte Additive for High-Performance Potassium Metal Batteries
- 2023
-
In: Advanced Functional Materials. - 1616-3028 .- 1616-301X. ; 33:48
-
Journal article (peer-reviewed)abstract
- Potassium metal batteries (KMBs) coupled with layered transition metal oxides as cathode materials are a promising energy−storage technology owing to low cost and high capacity. However, uncontrollable dendritic growth in the K−metal anode and chemical reactivity of the layered transition metal oxide cathode against the electrolyte solution cause KMBs to suffer from low Coulombic efficiency, rapid capacity fading, and critical safety issues. In this study, an electrolyte engineering strategy is introduced by introducing adiponitrile (ADN) as a dual−functional electrolyte additive containing an electron−rich nitrile group (C≡N) in its molecule structure. Thus, the addition of 1 wt.% ADN can alter the chemical properties of the electrolyte solution, thereby improving the anode−electrolyte and cathode−electrolyte interfacial stabilities in KMBs. The formation of a potassiophilic compound with C≡N in the solid electrolyte interphase layer can guide the uniform electrodeposition of K and suppress the dendritic growth in the K−metal. Moreover, C≡N forms a strong coordination bond with the oxidized transition metal, leading the reversible redox reactions by mitigating the undesirable disproportionation reaction and improving the thermal stability of the layered transition metal oxide cathode. Computational calculations and experimental characterizations are used to verify the role of ADN additive in enhancing the electrochemical properties of KMBs.
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| 37. |
- Park, Jimin, et al.
(author)
-
Introduction of a nitrate anion with solubility mediator in a carbonate-based electrolyte for a stable potassium metal anode
- 2024
-
In: Energy Storage Materials. - 2405-8297. ; 69
-
Journal article (peer-reviewed)abstract
- In this study, sodium nitrate (NaNO3) dissolves in a carbonate electrolyte for K-metal batteries (KMBs) using a dimethylacetamide (DMA) solvent with a higher Gutmann donor number than that of NO3−. The K-metal anode in 0.02 M NaNO3 electrolyte exhibits enhanced stability due to the modified solid-electrolyte interphase (SEI) layer resulting from the preferential reduction of NaNO3. Reduced NaNO3 forms ionically conductive and mechanically robust compounds in the SEI layer. This compound plays a critical role in altering the morphology of electrodeposited K-metal from dendritic to spherical, reducing the barrier energy of nucleation potential for K-ions. These unique features make K-metal highly resistant to dendrite formation and aggressive electrolyte chemistry. Therefore, the K-metal anode in the proposed electrolyte containing 0.02 M NaNO3 additive ensures excellent cycle life with stable Coulombic efficiency in both symmetrical K/K half cells and full-cells coupled with a Prussian green FeFe(CN)6 cathode.
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| 38. |
- Park, Jimin, et al.
(author)
-
Regulating the Solvation Structure of Electrolyte via Dual–Salt Combination for Stable Potassium Metal Batteries
- 2023
-
In: Advanced Science. - 2198-3844 .- 2198-3844. ; 10:16
-
Journal article (peer-reviewed)abstract
- Batteries using potassium metal (K-metal) anode are considered a new type of low-cost and high-energy storage device. However, the thermodynamic instability of the K-metal anode in organic electrolyte solutions causes uncontrolled dendritic growth and parasitic reactions, leading to rapid capacity loss and low Coulombic efficiency of K-metal batteries. Herein, an advanced electrolyte comprising 1 M potassium bis(fluorosulfonyl)imide (KFSI) + 0.05 M potassium hexafluorophosphate (KPF6) dissolved in dimethoxyethane (DME) is introduced as a simple and effective strategy of regulated solvation chemistry, showing an enhanced interfacial stability of the K-metal anode. Incorporating 0.05 M KPF6 into the 1 M KFSI in DME electrolyte solution decreases the number of solvent molecules surrounding the K ion and simultaneously leads to facile K+ de-solvation. During the electrodeposition process, these unique features can lower the exchange current density between the electrolyte and K-metal anode, thereby improving the uniformity of K electrodeposition, as well as potentially suppressing dendritic growth. Even under a high current density of 4 mA cm−2, the K-metal anode in 0.05 M KPF6-containing electrolyte ensures high areal capacity and an unprecedented lifespan with stable Coulombic efficiency in both symmetrical half-cells and full-cells employing a sulfurized polyacrylonitrile cathode.
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| 39. |
- Park, Jimin, et al.
(author)
-
Stable Solid Electrolyte Interphase for Long-Life Potassium Metal Batteries
- 2022
-
In: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 7:1, s. 401-409
-
Journal article (peer-reviewed)abstract
- Potassium (K) is considered to be the most suitable anode material for rechargeable K batteries because of its high theoretical capacity (686 mAh g(-1)) and low redox potential (-2.93 V vs SHE). However, uneven electrodeposition of K during cycling usually leads to the growth of dendrites, resulting in low Coulombic efficiency and compromising battery safety. Herein, we develop a strategy for stabilizing K metal through simple interface control. The conductive passivation layer can be controllably designed by a spontaneous chemical reaction when a K metal foil is kept in contact with a liquid-phase potassium-polysulfide (PPS); this guides the formation of an electronically and ionically conductive solid electrolyte interphase layer including K2S compound, enabling dense K plating with a dendrite-free morphology. Compared to the bare K metal anode, the PPS-treated K metal anode demonstrates superior cycling stability in symmetric half cells and full cells using a TiS2 cathode under practical constraints.
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| 40. |
- Ren, Hanyu, et al.
(author)
-
Untangling the effects of climate variation and human interference on grassland dynamics in North China
- 2024
-
In: Land Degradation and Development. - 1085-3278 .- 1099-145X. ; 35:1, s. 467-483
-
Journal article (peer-reviewed)abstract
- Climatic and anthropogenic disturbances play pivotal roles in shaping the dynamics of grassland. Quantifying their impacts on grassland variation is essential to ensure sustainable grassland management. In this study, we employed the Thornthwaite Memorial and Carnegie-Ames-Stanford-approach (CASA) models to investigate the spatiotemporal effects of these two variables on grassland variation in northern China from 2000 to 2016, using the net primary productivity (NPP) as a measure. Our findings reveal that approximately 25.92% of the grassland in northern China experienced degradation, while restored grasslands occupied 45% of the total grassland area. The average grassland actual NPP (ANPP) and human-induced NPP decreased at rates of -0.60 and -5.62 gC m-2 a-1, respectively. Conversely, potential NPP exhibited an upward trend with an average increase of 2.27 gC m-2 a-1. Furthermore, grassland ANPP showed a projected increase in most parts of northern China. Climate change emerged as the primary driver for grassland restoration in Xinjiang, Qinghai, and Inner Mongolia, leading to an increase of 21582.79 Gg C in grassland NPP. In contrast, human activities were the dominant catalysts for grassland degradation, resulting in a reduction of 51932.3 Gg C in grassland NPP. Human-induced grassland degradation was ubiquitous in northwest and northeast China. With the exception of slope grassland, climate change primarily influenced the restoration of most grassland types, while human activities were the primary cause of degradation. Our analysis indicated a strong correlation between temperature and grassland degradation, while precipitation played a pivotal role in grassland restoration in northern China. Human interference demonstrated both positive and negative impacts on grassland changes. In conclusion, the increase in precipitation and the implementation of ecological restoration plans have effectively promoted the restoration of grasslands in northern China.
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| 41. |
- Ren, Hanyu, et al.
(author)
-
Vegetation response to changes in climate across different climate zones in China
- 2023
-
In: Ecological Indicators. - 1470-160X .- 1872-7034. ; 155
-
Journal article (peer-reviewed)abstract
- Vegetation growth is sensitive to climate change. The complex climate types of China pose great challenges to the sustainable management of vegetation on global change. Therefore, this study used Enhanced Vegetation Index (EVI) as an indicator to explore the spatiotemporal dynamics of vegetation and their driving factors in different climatic zones of China to provide theoretical support for sustainable vegetation management in different climate zones in the future. The results showed that vegetation exhibited considerable clustering patterns in the country, with high and low values concentrated in the eastern and western regions, respectively. From 2001 to 2020, both at regional and pixel scales, vegetation in China showed a significant greening trend. EVI displayed a noticeable increase within temperate and subtropical areas. The only exception is observed in the eastern coastal area of the North China Plain and Yangtze River Delta region, which experienced evident degradation trend. During this period, China's climate showed an overall trend towards warming and humidification with drying trends observed mainly over the western regions. The impact of climate changes resulted in EVI dynamics that vary over time and space. The vegetation change in China was mainly derived by changes in precipitation and radiation rather than temperature, especially in temperate and subfrigid regions. Precipitation was the main driving factor for vegetation greening in tropical and temperate regions, while radiation and temperature were the dominant climate factor for vegetation greening in subfrigid and subtropical regions, respectively. When precipitation was no longer a limiting factor for vegetation growth, the effect of temperature or radiation increases. In addition, the positive impact of precipitation on plant growth in temperate regions was much greater than that of radiation and temperature, and this difference was much greater than in tropical, subtropical, and subfrigid regions.
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| 42. |
- Song, Luying, et al.
(author)
-
Synthesis of Two-Dimensional Metal-Organic Frameworks via Dehydrogenation Reactions on a Cu(111) Surface
- 2020
-
In: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 124:23, s. 12390-12396
-
Journal article (peer-reviewed)abstract
- Metal-organic frameworks prepared on surfaces (SMOFs) have been considered to have potential applications in various research fields. Traditionally, the SMOFs are prepared by coadsorbing organic ligands and metal atoms on surfaces. In this article, we successfully construct the SMOFs via the dehydrogenation reactions of aromatic amines on the Cu(111) surfaces. The dehydrogenated nitrogen radicals interact with the copper adatoms, forming the N-Cu-N bonds. Combining with the scanning tunneling microscopy and the density functional theory calculations, we obtain the structural models of the SMOFs.
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| 43. |
- Wang, Zijun, et al.
(author)
-
Quantifying the Spatiotemporal Changes in Evapotranspiration and Its Components Driven by Vegetation Greening and Climate Change in the Northern Foot of Yinshan Mountain
- 2024
-
In: Remote Sensing. - 2072-4292. ; 16:2
-
Journal article (peer-reviewed)abstract
- Evapotranspiration (E), a pivotal phenomenon inherent to hydrological and thermal dynamics, assumes a position of utmost importance within the intricate framework of the water–energy nexus. However, the quantitative study of E on a large scale for the “Grain for Green” projects under the backdrop of climate change is still lacking. Consequently, this study examined the interannual variations and spatial distribution patterns of E, transpiration (Et), and soil evaporation (Eb) in the Northern Foot of Yinshan Mountain (NFYM) between 2000 and 2020 and quantified the contributions of climate change and vegetation greening to the changes in E, Et, and Eb. Results showed that E (2.47 mm/a, p < 0.01), Et (1.30 mm/a, p < 0.01), and Eb (1.06 mm/a, p < 0.01) all exhibited a significant increasing trend during 2000–2020. Notably, vegetation greening emerged as the predominant impetus underpinning the augmentation of both E and Eb, augmenting their rates by 0.49 mm/a and 0.57 mm/a, respectively. In terms of Et, meteorological factors emerged as the primary catalysts, with temperature (Temp) assuming a predominant role by augmenting Et at a rate of 0.35 mm/a. Temp, Precipitation (Pre), and leaf area index (LAI) collectively dominated the proportional distribution of E, accounting for shares of 32.75%, 28.43%, and 25.01%, respectively. Within the spectrum of predominant drivers influencing Et, Temp exerted the most substantial influence, commanding the largest proportion at 33.83%. For Eb, the preeminent determinants were recognized as LAI and Temp, collectively constituting a substantial portion of the study area, accounting for 32.10% and 29.50%, respectively. The LAI exerted a pronounced direct influence on the Et, with no significant effects on E and bare Eb. Wind speed (WS) had a substantial direct impact on both E and Et. Pre exhibited a strong direct influence on E, Et, and Eb. Relative humidity (RH) significantly affected E directly. Temp primarily influenced Eb indirectly through radiation (Rad). Rad exerted a significant direct inhibitory effect on Eb. These findings significantly advanced our mechanistic understanding of how E and its components in the NFYM respond to climate change and vegetation greening, thus providing a robust basis for formulating strategies related to regional ecological conservation and water resources management, as well as supplying theoretical underpinnings for constructing sustainable vegetation restoration strategies involving water resources in the region.
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| 44. |
- Xiong, Shizhao, 1985, et al.
(author)
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Mechanical Failure of Solid-State Electrolyte Rooted in Synergy of Interfacial and Internal Defects
- 2023
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In: Advanced Energy Materials. - : Wiley. - 1614-6840 .- 1614-6832. ; 13:14
-
Journal article (peer-reviewed)abstract
- The mechanical failure of solid-state electrolytes induced by the growth of the lithium metal anode hinders the development of solid-state Li metal batteries with good safety and high energy density, and thus the understanding of the failure mechanism is of high importance for the application of solid-state lithium-metal batteries. Herein, a modified electro-chemo-mechanical model is built to bridge the dynamic relationship between the mechanical failure of solid-state electrolytes and the electrodeposition of lithium metal. The results, visualize evolution of local stress fields and the corresponding relative damage, and indicate that the generation of damage inside the solid-state electrolyte is rooted in a synergy of interfacial and internal defects. Compression by electrodeposited lithium inside interfacial defects and further transmission of stress inward in the electrolyte causes catastrophic damage, which is determined by the geometry of interfacial defects. Moreover, the internal defects of the solid-state electrolyte from sintering can influence the pathway of damage and work as the inner fountainhead for further damage propagation, and as such, the position and amount of the internal voids exhibit a more competitive role in the mechanical failure of solid-state electrolyte. Thus, the synergetic failure mechanism of solid-state electrolytes raised in this work provides a modeling framework to design effective strategies for state-of-the-art solid-state lithium-metal batteries.
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| 45. |
- Xu, Xieyu, et al.
(author)
-
Diffusion Limited Current Density: A Watershed in Electrodeposition of Lithium Metal Anode
- 2022
-
In: Advanced Energy Materials. - : Wiley. - 1614-6840 .- 1614-6832. ; 12:19
-
Journal article (peer-reviewed)abstract
- Lithium metal is considered to be a promising anode material for high-energy-density rechargeable batteries because of its high theoretical capacity and low reduction potential. Nevertheless, the practical application of Li anodes is challenged by poor cyclic performance and potential safety hazards, which are attributed to non-uniform electrodeposition of Li metal during charging. Herein, diffusion limited current density (DLCD), one of the critical fundamental parameters that govern the electrochemical reaction process, is investigated as the threshold of current density for electrodeposition of Li. The visualization of the concentration field and distribution of Faradic current density reveal how uniform electrodeposition of Li metal anodes can be obtained when the applied current density is below the DLCD of the related electrochemical system. Moreover, the electrodeposition of Li metal within broken solid electrolyte interphases preferentially occurs at the crack spots that are caused by the non-uniform electrodeposition of Li metal. This post-electrodeposition leads to more consumption of active Li when the applied current density is greater than the DLCD. Therefore, lowering the applied current density or increasing the DLCD are proposed as directions for developing advanced strategies to realize uniform electrodeposition of Li metal and stable interfaces, aiming to accelerate the practical application of state-of-the-art Li metal batteries.
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| 46. |
- Xu, Xieyu, et al.
(author)
-
Electro-Chemo-Mechanical Failure of Solid Electrolytes Induced by Growth of Internal Lithium Filaments
- 2022
-
In: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 34:49
-
Journal article (peer-reviewed)abstract
- Growth of lithium (Li) filaments within solid electrolytes, leading to mechanical degradation of the electrolyte and even short circuit of the cell under high current density, is a great barrier to commercialization of solid-state Li-metal batteries. Understanding of this electro-chemo-mechanical phenomenon is hindered by the challenge of tracking local fields inside the solid electrolyte. Here, a multiphysics simulation aiming to investigate evolution of the mechanical failure of the solid electrolyte induced by the internal growth of Li is reported. Visualization of local stress, damage, and crack propagation within the solid electrolyte enables examination of factors dominating the degradation process, including the geometry, number, and size of Li filaments and voids in the electrolyte. Relative damage induced by locally high stress is found to preferentially occur in the region of the electrolyte/Li interface having great fluctuations. A high number density of Li filaments or voids triggers integration of damage and crack networks by enhanced propagation. This model is built on coupling of mechanical and electrochemical processes for internal plating of Li, revealing evolution of multiphysical fields that can barely be captured by the state-of-the-art experimental techniques. Understanding mechanical degradation of solid electrolytes with the presence of Li filaments paves the way to design advanced solid electrolytes for future solid-state Li-metal batteries.
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| 47. |
- Xu, Xieyu, et al.
(author)
-
Role of Li-Ion Depletion on Electrode Surface: Underlying Mechanism for Electrodeposition Behavior of Lithium Metal Anode
- 2020
-
In: Advanced Energy Materials. - : Wiley. - 1614-6840 .- 1614-6832. ; 10:44
-
Journal article (peer-reviewed)abstract
- The application of lithium metal as an anode material for next generation high energy-density batteries has to overcome the major bottleneck that is the seemingly unavoidable growth of Li dendrites caused by non-uniform electrodeposition on the electrode surface. This problem must be addressed by clarifying the detailed mechanism. In this work the mass-transfer of Li-ions is investigated, a key process controlling the electrochemical reaction. By a phase field modeling approach, the Li-ion concentration and the electric fields are visualized to reveal the role of three key experimental parameters, operating temperature, Li-salt concentration in electrolyte, and applied current density, on the microstructure of deposited Li. It is shown that a rapid depletion of Li-ions on electrode surface, induced by, e.g., low operating temperature, diluted electrolyte and a high applied current density, is the underlying driving force for non-uniform electrodeposition of Li. Thus, a viable route to realize a dendrite-free Li plating process would be to mitigate the depletion of Li-ions on the electrode surface. The methodology and results in this work may boost the practical applicability of Li anodes in Li metal batteries and other battery systems using metal anodes.
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| 48. |
- Zhang, Chaofan, et al.
(author)
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In Situ Volume Change Studies of Lithium Metal Electrode under Different Pressure
- 2019
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In: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 166:15, s. A3675-A3678
-
Journal article (peer-reviewed)abstract
- Due to the high theoretical capacity density of 3680 mAh g(-1), lithium (Li) is considered as a promising anode for high-energy-density battery systems. However, its practical application is severely hampered by the invariable growth of Li dendrites and tremendous volume change during electrochemical plating-stripping process. Although real-time monitoring of the volume change is crucial for research and development of stable lithium anode, the studies are rare due to the lack of in-situ swelling equipment so far. Here, we report an in-situ volume change system to observe the thickness change of Li electrode at a resolution of micrometer during the electrochemical process. With a comprehensive design for this instrument, a continuously tunable pressure can be applied on the Li-Li symmetric cell to investigate the impact of pressure on the stability of Li electrode during cycling. We found that the higher pressure (similar to 850kPa) is beneficial for stabilizing Li electrode during plating/stripping process. Our results provide a perspective to investigate the electrochemical behavior of Li electrode. In addition, this instrument also shows great potential of in-situ volume change monitoring in other battery systems like silicon anode and solid-state batteries.
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