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Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly
2016 Vol.17 No.2 P.155-162
A novel organosilicon-based ionic plastic crystal as solid-state electrolyte for lithium-ion batteries
Abstract: A novel organosilicon-based ionic plastic crystal, N,N,N,-diethylmethyl-N-[(trimethylsilyl)methyl]ammonium bistrifluoromethane sulfonimide ([DTMA][TFSI]) was designed and synthesized as solid-state electrolyte for lithium-ion batteries. The chemical structure and the physical and electrochemical properties were characterized in detail. The ionic conductivity of [DTMA][TFSI] was improved significantly by doping with lithium oxalyldifluoroborate (LiODFB) and propylene carbonate (PC). An optimized plastic crystal composite ([DTMA][TFSI]:LiODFB:PC=8:1: molar ratio) as a solid-state electrolyte exhibited a decent cycling stability in LiFePO4/Li half-cell, with a specific discharge capacity of 144 mA·h/g and capacity retention of 94% after 50 cycles at C/20.
Key words: Organosilicon, Ionic plastic crystal, Solid-state electrolyte, Lithium-ion battery
创新点：1. 合成新型的有机硅基离子型塑晶材料；2. 将三元复合塑晶材料作为固态电解质在室温下用于锂离子电池。
方法：1. 通过热性能分析，得到材料的塑晶温度区间和融化熵值（图1和表1）；2. 通过电导率测试，确定塑晶掺杂对导电性能的影响（图2）；3. 通过对扣式电池的充放电性能、倍率性能、循环性能以及阻抗的测试（图4~7），得到塑晶复合物作为固态电解质的电化学性能以及电池循环的稳定性和可逆性。
结论：1. 合成新型有机硅基离子塑晶材料[DTMA][TFSI]，塑晶温度区间为-26 °C到54 °C；2. 在纯塑晶IPC中添加10% LiODFB和10% PC，得到复合物的电导率为1×10-4 S/cm，提高塑晶作为固态电解质在室温下应用的可行性；3. 将复合物用于LiFePO4/Li半电池测试，在C/20倍率下，电池的放电比容量为144 mA·h/g，库伦效率为99%。在50次循环后，容量保持率为94%；4. 测试结果表明，新型有机硅基离子塑晶的复合物可作为固态电解质材料应用于锂离子电池，以及更高能量密度的锂-硫和锂-空电池。
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DOI:
10.1631/jzus.A1500099
CLC number:
O646
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2024-08-27
Received:
2023-10-17
Revision Accepted:
2024-05-08
Crosschecked:
2016-01-25