A solid-state lithium metal battery with extended cycling and rate performance using a low-melting alloy interface

Abstract

Solid-state Li metal batteries (SSLMBs) have practical value in terms of operational application because of their superior energy density and security. However, the instability and inferior wettability of the interface between the Li metal anode and electrolyte lead to high interfacial impedance, which significantly impedes their practical applications. This study constructed a low-melting alloy interlayer using a facile in situ reaction for SSLMBs. The results demonstrate that the battery with the low-melting alloy interlayer (Ga–In–Sn–Li) exhibits excellent cycling and rate performance because of its excellent chemical stability and mechanical properties. Symmetrical cells with low-melting point alloy interlayers could stably cycle for over 1200 hours with low overpotential and critical current density as high as 2.2 mA cm⁻². This novel and feasible strategy has laid a solid foundation for the practical application of SSLMBs, and it has a certain universality for other solid-state batteries.