Chem. J. Chinese Universities ›› 2020, Vol. 41 ›› Issue (8): 1810.doi: 10.7503/cjcu20200252

• Physical Chemistry • Previous Articles     Next Articles

Improvement of Interface Stability Between Sulfide Solid Electrolyte Li10GeP2S12 and Lithium Metal

ZHOU Molin1,3, JIANG Xin2,3, YI Ting1,3, YANG Xiangguang4, ZHANG Yibo4   

  1. 1. Research Institute, Ningde Amperex Technology Limited, Ningde 352000, China;
    2. Advanced Product Department, Ningde Amperex Technology Limited, Ningde 352000, China;
    3. College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China;
    4. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
  • Received:2020-05-06 Online:2020-08-10 Published:2020-07-31

Abstract: Sulfide solid electrolyte Li10GeP2S12 exhibits extremely high ionic conductivity but relatively poor stability to lithium metal. After being modified by N-butyl-N-methylpiperidinium bis(fluorosulfonyl)imide together with lithium bis(fluorosulfonyl)imide, a thin and dense solid electrolyte interphase(SEI) was formed in situ at the Li|Li10GeP2S12 interface. Besides, the ionic liquid with certain liquidity is able to penetrate into the interior grains of Li10GeP2S12 to construct abundant lithium ion diffusion channels, which could alleviate the high impedance problem caused by the thermodynamically unstable interface. The modified Li|Li10GeP2S12|Li symmetric cell attains a stable cycle life of over 1500 h with the polarization voltage of 30 mV at 0.1 mA/cm2. In addition, the interface modified Li|Li10GeP2S12|LiFePO4 cell delivers an initial discharge capacity of 148.1 mA·h/g at 0.2C with the voltage range of 2.5-3.6 V and the first cycle Coulombic efficiency of 95.8%. The capacity retention is still 90.1% after 30 cycles, showing an improved cycling stability.

Key words: Sulfide solid electrolyte, Electrolyte/electrode interface, Ionic liquid

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