| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- Jin, Rui, et al.
(författare)
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High Li+ Ionic Flux Separator Enhancing Cycling Stability of Lithium Metal Anode
- 2018
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Ingår i: ACS Sustainable Chemistry and Engineering. - : AMER CHEMICAL SOC. - 2168-0485. ; 6:3, s. 2961-2968
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Tidskriftsartikel (refereegranskat)abstract
- The metallic lithium anode provides unparalleled opportunities for rechargeable batteries with very high energy density. A main problem hindering the development of cells using metallic lithium anodes stems from the electrochemical instability of the interface between metallic lithium and organic liquid electrolytes. This paper reports an approach rationally designing the surface characteristic of separator for stable, dendrite-free operation of lithium-metal batteries. A unique polymer multilayer PEI(PAA/PEO)(3) was fabricated on the microporous polyethylene (PE) separator by a simple layer-by-layer (LbL) assembly process, which maintains the pore structure and thickness of PE separator but remarkably enhances the ionic conductivity (from 0.36 mS cm(-1) to 0.45 mS cm(-1)) and Li+ transference number (from 0.37 to 0.48), as well as stabilizes lithium metal anodes against the reaction with liquid electrolytes during storage and repeated charge/discharge cycles, which is responsible for restraining the electrode polarization and the formation of lithium dendrites, and therefore endows lithium metal batteries with long-term cycling at high columbic efficiency and excellent rate capability, as well as the improved safety.
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| 7. |
- Liang, Huali, et al.
(författare)
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Highly-ordered microstructure and well performance of LiNi0.6Mn0.2Co0.2O2 cathode material via the continuous microfluidic synthesis
- 2020
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 394
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Tidskriftsartikel (refereegranskat)abstract
- Ni-rich layered oxides are potential cathode candidate's materials for Li-ion batteries due to their low cost and high energy density. However, it is difficult to reproducibly prepare uniformly distributed element and wellcontrolled morphology of Ni-rich layered oxide particles. This study develops a continuous microfluidic reaction process to synthesize spherical carbonate precursors (Ni0.6Mn0.2Co0.2CO3). The as-synthesized LiNi0.6Co0.2Mn0.2O2 materials exhibit well-defined microsphere morphology, uniform particles size distribution, better thermal stability and homogeneous transition metal distribution, due to the excellent mixing, well mass and heat transfer rate during the microfluidic reaction. Moreover, the as-prepared LiNi0.6Co0.2Mn0.2O2 materials achieve higher initial capacity, excellent electrochemical reversibility and capacity retention than that of the samples prepared by traditional co-precipitation. Therefore, our results demonstrate that microfluidic reaction is a simple and effective synthesis technology for preparing Ni-rich layered cathode.
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| 8. |
- 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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| 9. |
- Lv, Fei, et al.
(författare)
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Challenges and development of composite solid-state electrolytes for high-performance lithium ion batteries
- 2019
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Ingår i: Journal of Power Sources. - : Elsevier. - 0378-7753 .- 1873-2755. ; 441
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Forskningsöversikt (refereegranskat)abstract
- The safety concerns and the pursuit of high energy density have stimulated the development of high-performance solid-state lithium ion batteries. Therefore, the key component in solid-state lithium batteries, i.e. the solid-state electrolytes, also has attracted tremendous attention due to its non-flammability and good adaptability to high-voltage cathodes/lithium metal anodes. An in-depth understanding of the existing problems of solid-state electrolytes and proposed strategies for addressing these problems is crucial for the efficient design of high-performance solid-state electrolytes. In this review, we systematically summarized the current limitations of composite solid-state electrolytes and efforts to overcome them, and gave some proposals for the future perspectives of solid-state electrolytes with the aim to provide practical guidance for the researchers in this area.
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| 10. |
- Mao, Xufeng, et al.
(författare)
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Polyethylene separator activated by hybrid coating improving Li+ ion transference number and ionic conductivity for Li-metal battery
- 2017
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Ingår i: Journal of Power Sources. - : Elsevier. - 0378-7753 .- 1873-2755. ; 342, s. 816-824
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Tidskriftsartikel (refereegranskat)abstract
- Low Li+ ion transference number is one fatal defect of the liquid LiPF6 electrolyte for Li-metal anode based batteries. This work aims to improve Li+ ion transference number and ionic conductivity polyethylene (PE) separators. By a simple dip-coating method, the water-borne nanosized molecular sieve with 3D porous structure (ZSM-5) can be coated on PE separators. Especially, the Li+ ion transference number is greatly enhanced from 0.28 to 0.44, which should be attributed to the specific pore structure and channel environment of ZSM-5 as well as the interaction between ZSM-5 and electrolyte. Compared with the pristine PE separator, the ionic conductivity of modified separators is remarkably improved from 0.30 to 0.54 mS cm(-1). As results, the C-rate capability and cycling stability are both improved. The Li-metal battery using the ZSM-5-modified PE separator keeps 94.2% capacity after 100 cycles. In contrast, the discharge capacity retention of the battery using pristine PE is only 74.7%.
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