| 1. |
- Jin, Feng, et al.
(författare)
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Enhanced rate capability and high-voltage cycling stability of single-crystal nickel-rich cathode by surface anchoring dielectric BaTiO3
- 2022
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier. - 0021-9797 .- 1095-7103. ; 619, s. 65-74
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Tidskriftsartikel (refereegranskat)abstract
- The single-crystal Ni-rich Li(NixCoyMn1_x_y)O-2 cathode (NCM) demonstrates better cycle performance, enhanced tap density and improved mechanical structure stability, compared with polycrystalline NCM. However, limited Li+ transports, (003) plane slips and microcracks in large single particles hinder rate capability and cycle performance. To overcome these shortcomings, single-crystal NCM cathodes have been modified by nanosized tetragonal BaTiO3. Due to the dielectric properties, BaTiO(3 )particles induce electric field concentration at the BaTiO3-NCM-electrolyte interface. Thus, a large amount of lithium vacancies can be formed, providing sufficient sites for the hopping diffusion of lithium ions, thereby significantly enhancing the diffusion coefficient of Li+. Moreover, the redistribution of charges can inhibit the formation and accumulation of cathode-electrolyte-interface. Owing to the synergetic effect of BaTiO3, the BT-modified single-crystal NCM with the optimized loading shows a remarkable initial discharge capacity of 138.5 mAh g(_1) and maintains 53.8% of its initial discharge capacity after 100 cycles under 5C at 4.5 V cut-off voltage. Overall, the proposed dielectric cathode-electrolyte-interface strategy can enhance Li+ ion transport and stabilize the interface structure, leading to improved rate performance. Meanwhile, the diffusion-induced state of charge gradient can also be inhibited, resulting in high structure stability of single-crystal NCMs under high rate and cut-off voltage cycling. (C) 2022 Elsevier Inc. All rights reserved.
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| 2. |
- Liang, Wenbiao, et al.
(författare)
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Synthesis of single-crystal LiNi0.8Co0.1Mn0.1O2 materials for Li-ion batteries by microfluidic technology
- 2023
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 464
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Tidskriftsartikel (refereegranskat)abstract
- Single-crystal LiNixMnyCo1-x-yO2 (SC-NMC) cathode with electro-chemo-mechanically compliant microstructure is regarded as a promising candidate for high-energy-density lithium ion battery. However, the research of Ni-rich SC-NCM still lags behind its corresponding polycrystalline cathode materials, mainly due to the difficulties in synthesis. Herein, the single-crystal LiNi0.8Mn0.1Co0.1O2 cathode (SC-NCM811) was successfully synthesized by microfluidic technology combined with the solid-state lithiation process. The nano-sized Ni0.8C- o0.1Mn0.1(OH)2 precursor prepared via microfluidic technology enhances its accessibility to lithium salts, thus exhibiting high chemical activity for lithiation reaction. As a result, the optimized SC-NCM811 cathode shows relatively small-scale grain size (<3 mu m), low cation mixing and well layered structure, which is beneficial to electrochemical kinetics and redox reversibility. The electrochemical characterization results further reveal that the optimized SC-NCM811 cathode can well balance the cycle performance and rate capability, showing good electrochemical performance. Overall, microfluidic technology is expected to provide a new strategy for pre-paring single-crystal Ni-rich cathode materials, which may extend to the commercial application of other cathode materials.
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| 3. |
- Wang, Shuai, et al.
(författare)
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In Situ Synthesis of Tungsten-Doped SnO2 and Graphene Nanocomposites for High-Performance Anode Materials of Lithium-Ion Batteries
- 2017
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 9:20, s. 17163-17171
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Tidskriftsartikel (refereegranskat)abstract
- The composite of tungsten-doped SnO2 and reduced graphene oxide was synthesized through a simple one pot hydrothermal method. According to the structural characterization of the composite, tungsten ions were doped in the unit cells of tin dioxide rather than simply attaching to the surface. Tungsten-doped SnO2 was in situ grown on the surface of graphene sheet to form a three-dimensional conductive network that enhanced the electron transportation and lithium-ion diffusion effectively. The issues of SnO2 agglomeration and volume expansion could be also avoided because the, tungsten-doped SnO2 nanoparticles were homogeneously distributed on a graphene sheet. As a result, the nanocomposite electrodes of tungsten-doped SnO2 and reduced graphene oxide exhibited an excellent long-term cycling performance. The residual capacity was still as high as 1100 mA h g(-1) at 0.1 A g(-1) after 100 cycles. It still remained at 776 mA h g(-1) after 2000 cycles at the current density of lA g(-1).
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| 4. |
- Wang, Yanan, et al.
(författare)
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Gel Polymer Electrolyte with High Li+ Transference Number Enhancing the Cycling Stability of Lithium Anodes
- 2019
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 11:5, s. 5168-5175
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Tidskriftsartikel (refereegranskat)abstract
- Lithium anodes suffer from severe safety problems in liquid electrolyte systems that result from an unstable Li plating/stripping process and Li dendrite growth, leading to rapid degradation of Li metal batteries. A polyethylene (PE)-supported gel polymer electrolyte (GPE) with excellent electrolyte uptake/retention capability was simply prepared in this paper by the construction of cross-linked polymer networks (PNs) on the surface of a poly(ethylenimine)-primed PE separator to stabilize the lithium anode. The highly delocalized negative charge of p-styrene sulfonate groups on PNs plays a role in regulating the Li+ and anion transport, giving rise to a high Li+ transference number. This GPE extended the electrochemical stability to 4.8 V and improved the stability of interface between the electrolyte and lithium metal anode (reduced overpotential and suppressed lithium dendrites) during storage and repeated lithium plating/stripping cycling. The Li metal anode-based battery employing this GPE exhibits excellent cycling stability and C-rate capability.
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| 5. |
- Wang, Yanan, et al.
(författare)
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Polyethylene separators modified by ultrathin hybrid films enhancing lithium ion transport performance and Li-metal anode stability
- 2018
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 259, s. 386-394
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Tidskriftsartikel (refereegranskat)abstract
- Poor stability of lithium metal anodes in liquid electrolytes hinders its practical application in rechargeable batteries with very high energy density. Herein, we present an approach to tackle the intrinsic problems of Li metal anodes from the standpoint of separators. By a facile and versatile method based on mussel-inspired surface chemistry, a hybrid polydopamine/octaammonium POSS (PDA/POSS) coating was spontaneously formed on the surface of PE separators through the self-polymerization and strong adhesion feature of dopamine. This ultrathin PDA/POSS coating endows PE separators with different surface characteristics while keeping its microporous structure almost unchanged. The altered surface characteristics influence the separator/electrolyte interaction, and lead to remarkable enhanced ionic conductivity (from 0.36 mS cm−1 to 0.45 mS cm−1) and Li+ ion transference number (from 0.37 to 0.47) of PE separators as well as the improved stability of lithium/electrolyte interface, which effectively decreases the electrode polarization and suppresses the lithium dendrites formation, contributing to superior C-rates capability and cycling performance of cells.
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| 6. |
- Zhang, Meihong, et al.
(författare)
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A simple and rapid route for synthesizing the nanosized g-C3N4 materials with narrow bandgap and their photocatalytic activity
- 2023
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Ingår i: Surface and Interface Analysis. - : John Wiley & Sons. - 0142-2421 .- 1096-9918. ; 55:1, s. 63-70
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Tidskriftsartikel (refereegranskat)abstract
- The graphitic carbon nitride (g-C3N4) materials with many intriguing properties have attracted much attention in photocatalysis. The photocatalytic activity of g-C3N4 is hindered by serious aggregation and limited exposed active sites. Herein is shown that nanosized g-C3N4 can be simply obtained by a superfast high-pressure homogenization approach. The high-pressure homogenization treatment can provide strong force to cut and/or to exfoliate the bulk g-C3N4 into nanosized g-C3N4 with good dispersion. Moreover, choosing different solvents during treatment can cause a different surface structure of as-prepared nanosized g-C3N4. In addition, the narrow bandgap properties, the high photogenerated charge carrier separation, and the transport abilities are achieved in as-prepared nanosized g-C3N4 because of the retaining conjugated C3N4 system. Specifically, the photocatalytic activities of as-prepared nanosized g-C3N4 have been significantly enhanced in terms of degradation of organic dye Rhodamine B (RhB) under visible light irradiation (10 times higher than that of bulk g-C3N4). These findings can provide a promising and simple approach to the exfoliation, nanonization, and surface functionalization of 2D layered materials.
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| 7. |
- Chen, Wenju, et al.
(författare)
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Porous cellulose diacetate-SiO2 composite coating on polyethylene separator for high-performance lithium-ion battery
- 2016
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 147, s. 517-524
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Tidskriftsartikel (refereegranskat)abstract
- The developments of high-performance lithium ion battery are eager to the separators with high ionic conductivity and thermal stability. In this work, a new way to adjust the comprehensive properties of inorganic-organic composite separator was investigated. The cellulose diacetate (CDA)-SiO2 composite coating is beneficial for improving the electrolyte wettability and the thermal stability of separators. Interestingly, the pore structure of composite coating can be regulated by the weight ratio of SiO2 precursor tetraethoxysilane (TEOS) in the coating solution. The electronic performance of lithium ion batteries assembled with modified separators are improved compared with the pristine PE separator. When weight ratio of TEOS in the coating solution was 9.4%, the composite separator shows the best comprehensive performance. Compared with the pristine PE separator, its meltdown temperature and the break-elongation at elevated temperature increased. More importantly, the discharge capacity and the capacity retention improved significantly.
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| 8. |
- Chen, Wenju, et al.
(författare)
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Water-Based Organic-Inorganic Hybrid Coating for a High-Performance Separator
- 2016
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:7, s. 3794-3802
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Tidskriftsartikel (refereegranskat)abstract
- With the development of electric vehicles, the traditional polyolefin separators can not meet the increasing requirements of lithium ion batteries with high power density, high energy density, and high safety performance. Herein, a novel water-based binder is synthesized by grafting carboxyl groups onto cellulose diacetate. When the polyethylene (PE) separator is coated by this binder and SiO2 nanoparticles, the thermal shrinkage of the modified separator is observed to be almost 0% after exposure at 200 degrees C for 30 min. The puncture strength significantly increase from 5.10 MPa (PE separator) to 7.64 MPa. More importantly, the capacity retention of the cells assembled with modified separators after 100 cycles at 0.5 C increase from 73.3% (cells assembled with PE separator) to 81.6%, owing to the excellent electrolyte uptake and the good compatibility with lithium electrode. Besides, the modified separator shows excellent surface stability after 100 cycles. Considering the above excellent properties, this composite separator shows high potential to be used in lithium ion batteries with high power density and safety.
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| 9. |
- Chi, Mingming, et al.
(författare)
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Excellent rate capability and cycle life of Li metal batteries with ZrO2/POSS multilayer-assembled PE separators
- 2016
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Ingår i: NANO ENERGY. - : Elsevier BV. - 2211-2855. ; 28, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Today there are new interests in using metallic lithium as anode materials in lithium batteries because of its extremely large theoretical specific capacity. However, the low cycle efficiency and the lithium dendrite formation during repeated charge/discharge cycles hinder the practical application of metallic lithium anodes. Herein, we report a distinctive ZrO2/POSS multilayer deposited on PE separators by a simple layer-by-layer (LbL) self-assembly process to enable excellent rate capability and cycle life of lithium metal batteries. The ZrO2/POSS multilayer on PE separators weakens the solvation effect of lithium ions and significantly enhances the electrolyte uptake of separators, which is responsible for the enhanced ionic conductivity and Li+ transference number, as well as the improved Li/electrolyte interfacial stability. These advantageous characteristics of the resulting PE separators effectively decrease the electrode polarization and protect lithium metal anodes against lithium dendrites formation during repeated charge/discharge cycles, endowing LiCoO2/Li unit cells with both excellent electrochemical performance and high safety. The fundamental understanding on the effects of the micro/nano structures and properties of separators on the important electrochemistry processes at electrode/electrolyte interface of battery systems may lead to new approaches to tackle the intrinsic problems of Li metal anodes for energy storage applications.
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| 10. |
- Fu, Lixin, et al.
(författare)
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Nanocoating inside porous PE separator enables enhanced ionic transport of GPE and stable cycling of Li-metal anode
- 2019
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Ingår i: Research on chemical intermediates (Print). - : Springer Science and Business Media LLC. - 0922-6168 .- 1568-5675. ; 45:10, s. 4959-4973
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a simple and feasible method for preparing gel polymer electrolyte (GPE) with good ionic transport properties and mechanical stability is proposed. A ZrO2/KH570/PU/P123 layer was formed on the outer and inner pore surfaces of PE separator before in situ polymerization by a simple one-step dipping coating process. This coating layer changes the PE separator surface from hydrophobic to hydrophilic, and therefore facilitates the uniform spreading of the GPE precursor solution on the PE surface to enable the formation of highly uniform GPE. Moreover, it effectively compensates the negative effects of in situ gelatinization on the ionic transport behavior of the final PE-supported GPE. This GPE possesses excellent ion transport properties and mechanical stability, as well as improves the static and dynamic interfacial stability with lithium metal anode. When using metallic lithium and LiCoO2 to assemble cells, this PE-supported GPE affords improved C-rate capability, cycling performance and effective dendrite inhibition. [GRAPHICS] .
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