In Situ Generated Electron-Blocking Lih Enabling An Unprecedented Critical Current Density of Over 15Ma Cm-2 for Solid-State Hydride Electrolytes.

Abstract

LiBH4 is a promising solid-state electrolyte due to its thermodynamic stability to Li. However, poor Li-ion conductivities at room temperature, low oxidative stabilities and severe dendrite growth hamper its application. Herein, weadopted a partial dehydrogenation strategy to in situ generate an electronic blocking layer dispersed of LiH, addressing the above three issues simuteneously. The electrically insulated LiH reduces the electronic conductivity by two orders of magnitude, leading to a 32.0-times higher critical electrical bias for dendrite growth on the particle surfaces than that of the counterpart. Additionally, this layer not only promotes the Li-ion conductance by stimulating coordinated rotations of BH4 - and B12 H12 2- , contributing to a Li-ion conductivity of 1.38 × 10-3 S cm-1 at 25 °C, but also greatly enhances oxidation stability by localizing the electron density on BH4 - , extending its voltage window to 6.0V. Consequently, this electrolyte exhibits an unprecedented critical current density of 15.12mA cm-2 at 25 °C, long-term Li plating and stripping stability for 2700h, and a wide temperature window for dendrite inhibition from -30 to 150 °C. Its Li-LiCoO2 cell displayed high reversibility within 3.0 to 5.0V. We believe this work provides a clear direction for solid-state hydride electrolytes. This article is protected by copyright. All rights reserved.