Achieving Dendrite-Free Solid-State Lithium-Metal Batteries via In Situ Construction of Li3P/LiCl Interfacial Layers.

Abstract

Hybrid solid electrolyte (HSE) exhibits potential as a solid electrolyte due to its satisfactory Li+ conductivity, superior flexibility, and optimal interface compatibility. However, the inadequate wettability of the Li/HSE interface leads to significant contact impedance, thus fostering the formation of Li dendrites and limiting their practical applicability. Here, a straightforward strategy to enhance the interfacial wettability between Li and HSE and promote the uniform migration of Li+ by in situ construction of a multifunctional interface consisting of Li3P/LiCl (PCl@Li) was created. The Li3P component acts as a Li+ channel, banishing Li+ diffusion obstacles within the interface layer, while the electronically insulating LiCl component acts as an electron-blocking shield at the Li/HSE interface, promoting uniform Li+ deposition and preventing the formation of Li dendrites. The interface impedance of the symmetric PCl@Li|HSE|PCl@Li battery decreases markedly from 230.2 to 47.4 Ω cm-2. Additionally, the battery demonstrates superb cycling stability for over 1300 h at 0.1 mA cm-2 and maintains a minimal overpotential of 32 mV at 30 °C. The PCl@Li|HSE|LiFePO4 battery shows an initial discharge-specific capacity of 135.6 mA h g-1 at 1 C, with a notable capacity retention of 87.0% (118.0 mA h g-1) after 500 cycles. This work provides a new facile strategy for all-solid-state batteries to address interface issues between Li electrodes and HSE.