Hierarchical Lithiophilic Structure Based on Liquid Metal Nanodroplet Enables High Coulombic Efficiency in Anode Free Lithium Metal Batteries

Abstract

Anode-free lithium metal batteries offer a practical route to achieve ultra-high energy density, yet their implementation is hindered by poor cycling stability and coulombic efficiency resulting from lithiophobic interfaces and nonuniform lithium deposition. To address these challenges, we design a lithium host material by incorporating gallium-based liquid metal nanodroplets into a 3D porous carbon framework (CF@GaInSn@C). This architecture effectively accommodates electrode volume changes and enables highly stable lithium plating/stripping behavior. The liquid metal nanodroplets function as an atomic composite core, providing abundant lithiophilic sites with low diffusion barriers that promote uniform lithium nucleation and lateral mass transport. This mechanism facilitates dense and homogeneous lithium deposition across the internal pores of the CF@GaInSn@C host. As a result, it demonstrates exceptional reversibility in half cells with a lithium electrode, maintaining a coulombic efficiency of 99.83% over 1500 cycles at 2 mA cm⁻² and 2 mAh cm⁻². Furthermore, anode-free full cells coupled with LiNi_0.8Co_0.1Mn_0.1O₂ cathodes deliver an average coulombic efficiency of 99.48% after 100 cycles at 0.5 C. This work demonstrates a promising structural design strategy based on liquid metal nanodroplets for regulating lithium deposition, highlighting their significant potential for application in high-performance anode-free lithium batteries.