Interfacial passivation by room-temperature liquid metal enabling stable 5 V-class lithium-metal batteries in commercial carbonate-based electrolyte

Abstract

Lithium (Li) metal is a promising anode for next-generation high-energy-density lithium-ion batteries (LIBs). Nevertheless, the stability of Li-metal anode is poor due to the severe corrosion by liquid electrolyte, uncontrollable growth of Li dendrites, huge volume expansion, and unstable solid electrolyte interphase (SEI). The high chemical reactivity of Li metal is the main inducement for the unstability of Li-metal anode. Herein, the stability of Li-metal anode is improved by passivating its surface with 3°C GaInSnZn liquid metal (LM). A Li-based alloy framework with submicron-scale grains is formed on the surface of Li metal through the spontaneous reaction between metallic Li and LM at room temperature. The Li-based alloy framework is tightly attached on Li metal without exfoliation and mechanical rupture even under bending and folding. The framework has higher Li+ diffusion coefficient, lower chemical reactivity, and better lithiophilicity than pure Li. Under the regulation of the multifunctional framework, the corrosion, uneven Li deposition, and unstable interface are effectively relieved even in a more corrosive carbonate-based electrolyte. When paired with 5 V-class cathodes, the full cells with passivated Li-metal anodes exhibit superior electrochemical performances. This passivation strategy also shows great potentials for high-reactive Na-metal and K-metal anodes.