An electron-blocking interface for garnet-based quasi-solid-state lithium-metal batteries to improve lifespan
Chang Zhang, Jiameng Yu, Yuanyuan Cui, Yinjie Lv, Yue Zhang, Tianyi Gao, Yuxi He, Xin Chen, T.X. Li, Tianquan Lin, Qixi Mi, Yi Yu, Wei Liu
Abstract
Abstract Garnet oxide is one of the most promising solid electrolytes for solid-state lithium metal batteries. However, the traditional interface modification layers cannot completely block electron migrating from the current collector to the interior of the solid-state electrolyte, which promotes the penetration of lithium dendrites. In this work, a highly electron-blocking interlayer composed of potassium fluoride (KF) is deposited on garnet oxide Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO). After reacting with melted lithium metal, KF in-situ transforms to KF/LiF interlayer, which can block the electron leakage and inhibit lithium dendrite growth. The Li symmetric cells using the interlayer show a long cycle life of ~3000 hours at 0.2 mA cm −2 and over 350 hours at 0.5 mA cm −2 respectively. Moreover, an ionic liquid of LiTFSI in C 4 mim-TFSI is screened to wet the LLZTO|LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM) positive electrode interfaces. The Li|KF-LLZTO | NCM cells present a specific capacity of 109.3 mAh g −1 , long lifespan of 3500 cycles and capacity retention of 72.5% at 25 °C and 2 C (380 mA g −1 ) with an average coulombic efficiency of 99.99%. This work provides a simple and integrated strategy on high-performance quasi-solid-state lithium metal batteries.