高等学校化学学报 ›› 2020, Vol. 41 ›› Issue (8): 1810.doi: 10.7503/cjcu20200252

• 物理化学 • 上一篇    下一篇

硫化物固态电解质Li10GeP2S12与锂金属间界面稳定性的改善研究

周墨林1,3, 蒋欣2,3, 易婷1,3, 杨向光4, 张一波4   

  1. 1. 宁德新能源科技有限公司研究院, 宁德 352000;
    2. 宁德新能源科技有限公司先进产品开发部, 宁德 352000;
    3. 厦门大学化学化工学院, 厦门 361005;
    4. 中国科学院长春应用化学研究所, 稀土资源利用国家重点实验室, 长春 130022
  • 收稿日期:2020-05-06 出版日期:2020-08-10 发布日期:2020-07-31
  • 通讯作者: 易婷,女,博士,工程师,主要从事锂离子电池研究.E-mail:yiting7@ATLBattery.com;杨向光,男,博士,研究员,主要从事催化与绿色化学研究.E-mail:xgyang@ciac.ac.cn E-mail:yiting7@ATLBattery.com;xgyang@ciac.ac.cn
  • 基金资助:
    中国博士后科学基金(批准号:2019M652249,2019M662229)资助.

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

摘要: 通过N-丁基-N-甲基哌啶双(氟磺酰)亚胺盐离子液体和双(氟磺酰)亚胺锂盐修饰了Li|Li10GeP2S12界面,并研究了界面的改性效果.研究结果表明,在界面处原位生成一层致密的固体电解质界面膜(SEI),具有一定流变性的离子液体可渗透到Li10GeP2S12晶粒内部;在0.1 mA/cm2的电流密度下,界面改性后的Li|Li10GeP2S12|Li对称电池可稳定循环1500 h以上,极化电压仅为30 mV.在2.5~3.6 V电压范围内,Li|Li10GeP2S12|LiFePO4电池在0.2C倍率下充放电循环的首次放电比容量为148.1 mA·h/g,库仑效率为95.8%,经过30次循环后容量保持率为90.1%.

关键词: 硫化物固态电解质, 电解质/电极界面, 离子液体

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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