Local Li+ Framework Regulation of a Garnet-Type Solid-State Electrolyte

作者：Sun, Furong; Yang, Yubo; Zhao, Shu; Wang, Yongtao; Tang, Mingxue; Huang, Qingzhen; Ren, Yang; Su, Heng; Wang, Boya; Zhao, Ning; Guo, Xiangxin; Yu, Haijun^*

来源：ACS Energy Letters, 2022, 7(8): 2835-2844.

DOI：10.1021/acsenergylett.2c01432

• TOTAL-ENERGY CALCULATIONS
• LITHIUM-ION CONDUCTION
• ELASTIC BAND METHOD
• DOPED LI7LA3ZR2O12
• CRYSTAL-STRUCTURE
• PHASE-TRANSITION
• TA
• GA
• 1ST-PRINCIPLES
• TEMPERATURE

Garnet-type solid-state electrolytes Li7La3Zr2O12 (LLZO) for high-energy-density batteries have attracted extensive attention. However, stabilizing the high-conductive cubic phase and improving its ionic conductivity remain challenges of current research. Here, a Ca-W dual-substitution strategy has been designed, and the effect of doping on cubic phase formation and Li+ mobility has been investigated thoroughly. The results indicated that the partial substitution of Ca2+ at the La3+ site and W6+ at the Zr4+ site can effectively stabilize the cubic phase while reducing the endothermic enthalpy during the synthesis. Moreover, Ca-W dual substitution regulates the local Li+ framework by increasing Li+ occupancy at the 96h site, which can significantly lower the Li+ migration barrier and thus improve the ionic conductivity by two orders of magnitude. This work addresses the challenge of stabilizing a highly conductive cubic phase with low-energy consumption and represents a major breakthrough in understanding how to improve the ionic conductivity by regulating local structures.

• 单位
  北京工业大学; 青岛大学