Liquid Metal Spheres Achieving Stable Residual SEI for Dendrite‐Free Lithium Metal Batteries

ABSTRACT Lithium dendrite growth represents the primary factor hindering the commercialization of high‐energy‐density lithium metal batteries, as it gives rise to safety hazards and low Coulombic efficiency. Surface morphology of deposited lithium is particularly affected by solid electrolyte interphase (SEI) and current collectors. Herein, we propose a current collector coated by spherical GaIn liquid metal nanoparticles encapsulated in a carbon layer (GaIn@C), which are spontaneously formed by the physical properties of liquid metal. This three‐dimensional spherical GaIn@C layer shows remarkable structure stability and avoids the tip effect during deposition of lithium, thus maintaining a stable residual SEI (rSEI) and dendrite‐free morphology over the repeated plating/stripping processes. The dendrite‐free lithium deposition behavior on GaIn@C layer was revealed via multiphysics simulation, ex‐situ deposition observation, in situ optical experiments, and in situ impedance analysis. Uniform deposition process of lithium half‐cell achieves a cycle life of up to 3500 h at an areal deposition capacity of 5 mAh cm −2 . Anode‐free full cell maintains specific capacity of 172.9 mAh g −1 after 100 cycles at 1C, with capacity retention of 99.9% and energy density of pouch battery exceed 410 Wh kg −1 . This study presents a general synthetic strategy for the construction of a current collector with stable residual SEI in dendrite‐free lithium metal batteries.