| 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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