Hierarchical‐Structured RGO@EGaIn Composites as Advanced Self‐Healing Anode for Room‐Temperature Liquid Metal Battery

Abstract Gallium‐based liquid metal (LM) has emerged as a promising candidate anode material for lithium‐ion batteries (LIBs), exhibiting high theoretical capacity, excellent electrode kinetics, and unique self‐healing ability. However, the liquid‐solid‐liquid transition during the electrochemical reactions can disrupt the solid electrolyte interphase (SEI) and damage the structural integrity, ultimately limiting the cycling stability. Here, hierarchical‐structured reduced graphene oxide coated eutectic gallium‐indium liquid metal particles (RGO@EGaIn LMPs) are synthesized using a facile self‐assembly strategy. The customized RGO@EGaIn electrode demonstrated impressive performance in both half‐cell and full‐cell configurations for LIBs. The morphological and phase transitions of RGO@EGaIn LMPs during the lithiation/delithiation processes are uncovered by real‐time in situ transmission electron microscopy tests. It is clarified that the presence of RGO in the hierarchical structure buffers the volume expansion of LMPs from ≈160% to 125% and provides a fast pathway for the rapid transfer of ions and electrons during the electrochemical reaction, which effectively enhances the electrochemical performance of the electrode. This work introduces a straightforward and effective method for preparing high‐performance room‐temperature liquid metal electrodes, representing a significant step forward toward the commercial application of liquid metal batteries.