An electron-blocking interface for garnet-based quasi-solid-state lithium-metal batteries to improve lifespan.

Zhang, Chang; Yu, Jiameng; Cui, Yuanyuan; Lv, Yinjie; Zhang, Yue; Gao, Tianyi; He, Yuxi; Chen, Xin et al. · Nat Commun · 2024

basic_science · Level V

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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<sub>6.4</sub>La<sub>3</sub>Zr<sub>1.4</sub>Ta<sub>0.6</sub>O<sub>12</sub> (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<sup>-2</sup> and over 350 hours at 0.5 mA cm<sup>-2</sup> respectively. Moreover, an ionic liquid of LiTFSI in C<sub>4</sub>mim-TFSI is screened to wet the LLZTO|LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub> (NCM) positive electrode interfaces. The Li|KF-LLZTO | NCM cells present a specific capacity of 109.3 mAh g<sup>-1</sup>, long lifespan of 3500 cycles and capacity retention of 72.5% at 25 °C and 2 C (380 mA g<sup>-1</sup>) 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.