In‐Situ Phase Separation Induced Yolk‐Shell Ga 2 O 3 @Carbon Nanofibers with Indium Nanoparticles for High‐Performance Lithium Storage

Gallium‐based liquid metal (Ga‐LM) anodes are of particular interest for lithium‐ion batteries owing to the unique liquid–solid phase transition. Nevertheless, the inevitable volume expansion of Ga‐LM during lithiation cannot be accommodated by rigid encapsulation, causing electrical isolation and rapid capacity decay. This study exploits the in‑situ phase separation of eutectic gallium indium (EGaIn) alloy, enabled by electrospinning‑derived carbon encapsulation, to generate a 3D carbon nanofiber (CNF) network comprising yolk‐shell Ga 2 O 3 @CNF structures and uniformly dispersed In nanoparticles. The preferential oxidation of Ga during carbonization drives phase separation of EGaIn into Ga 2 O 3 and metallic In, accompanied by the migration of In onto CNFs and the concomitant formation of yolk‑shell voids. As confirmed by finite element analysis (FEA) and density functional theory (DFT) calculations, the yolk‐shell structure accommodates volume change and relieves interfacial stress, while the In nanoparticles mitigate ohmic polarization and provide atomic‐scale Li adsorption sites. Benefiting from these merits, the phase‐separated electrode achieves outstanding cycling stability, with a capacity decay of merely 0.014% per cycle over 2000 cycles at 3 A g −1 , and a superior rate capability of 579.3 mAh g −1 at 3 A g −1 . This work establishes the in‑situ phase‑separation strategy as a compelling route toward high‑performance Ga‐LM‑based energy storage.