Enhancing Ion Transport and Suppressing Electron Conduction: a Hybrid Interlayer for Stable Garnet‐Based Solid‐State Batteries
Xing Xiang, Congkun Du, Rufang Zhao, Zhenzhen Zhao, Xin Ji, Dongyang Liu, Zhihan Li, Huihu Wang, Yanhua Zhang, Yun Zhao, Xinghui Liu, Fei Chen, Jian‐Fang Wu
Abstract
Abstract Cubic doped Li 7 La 3 Zr 2 O 12 s (LLZOs) are promising solid‐state electrolytes (SSE) for solid‐state lithium batteries due to their excellent lithium‐ion conductivities and electrochemical stability. However, they face the challenge of lithium dendrite growth. Here, a hybrid interlayer–alloy phases (LiZn, Li 22 Sn 5 , Li 5 Sn 2 ) and Li 2 O–is created by an in situ reaction between the modified layer Zn 2 SnO 4 (ZSO) on LLZO and lithium metal anodes. Benefiting from the synergistic effect of the fast lithium‐ion conduction of the Li 5 Sn 2 alloy, the strong affinity between the LiZn alloy and LLZO, and electronic insulator Li 2 O, a super‐conformal structure at the Li/ZSO‐LLZO interface is formed, effectively inhibiting the formation of lithium dendrites in ZSO‐LLZO SSE. Consequently, Li/ZSO‐LLZO/Li symmetric batteries deliver stable cycling (2500 h under 0.3 mA cm −2 at 25 °C and 6000 h under 0.5 mA cm −2 at 60 °C) performances with superhigh critical current densities of 2.5 mA cm −2 at 25 °C and 3.8 mA cm −2 at 60 °C. Moreover, the LiFePO 4 /ZSO‐LLZO/Li battery delivers capacities of 137.45 mAh g −1 under 1 C for 500 cycles and 111.78 mAh g −1 under a high rate of 2 C for 300 cycles. This work with a hybrid interlayer opens a boulevard for designing energy‐dense and long‐life solid‐state batteries.