TiO2-Induced Conversion Reaction Eliminating Li2CO3 and Pores/Voids Inside Garnet Electrolyte for Lithium-Metal Batteries

作者：Luo, Piao; Zeng, Binwen; Li, Wei; Zheng, Guangli; Su, Kexin; Liang, Lecheng; Song, Huiyu; Du, Li; Cui, Zhiming^*

来源：Advanced Functional Materials, 2023, 33(35).

DOI：10.1002/adfm.202302299

• contaminant Li2CO3
• garnet LLZO
• high critical current density
• LLTO

Garnet Li7La3Zr2O12 (LLZO) is regarded as a promising solid electrolyte due to its high Li+ conductivity and excellent chemical stability, but suffers from grain boundary resistance and porous structure which restrict its practical applications in lithium-metal batteries. Herein, a novel and highly efficient TiO2-induced conversion strategy is proposed to generate Li ion-conductive Li0.5La0.5TiO3, which can simultaneously eliminate the pre-existing pores/voids and contamination Li2CO3. The Li/LLZTO-5TiO(2)/Li symmetric cell exhibits a high critical current density of 1.1 mA cm(-2) at 25 degrees C, and the long-term lithium cycling stability of over 1500 h at 0.1 mA cm(-2). More importantly, the excellent performance of LLZTO-5TiO(2) electrolyte is verified by LiCoO2/LiFePO4 coupled full cells. For example, The LiCoO2 coupled full cell exhibits a significant discharge rate capacity of 108 mAh g(-1) at 0.1 C, and a discharge capacity retention rate of 91.23% even after 150 cycles of charge and discharge. COMSOL Multiphysics and density functional theory calculation reveal that LLZTO-5TiO(2) electrolyte has a strong lithium affinity and uniform Li ions distribution, which can improve the cycle stability of Li-metal batteries by preventing dendrite growth.