Encapsulating Ultrafine In2O3 Particles in Carbon Nanofiber Framework as Superior Electrode for Lithium-Ion Batteries

Indium oxide (In2O3) is a promising anode material for next-generation lithium-ion batteries and is prized for its high electrical conductivity, environmental friendliness, and high theoretical capacity. However, its practical application is significantly limited by severe volume expansion and contraction during the lithium insertion/extraction process. This volume change disrupts the solid electrolyte interphase (SEI) and degrades contact with the current collector, undermining battery performance. Although the nano-structured design of In2O3 can mitigate the volume effect to some extent, pure In2O3 nanomaterials are prone to agglomeration during frequent charging and discharging. The pure In2O3-based electrode shows a sustained and rapid capacity degradation. In this study, we embed ultrafine In2O3 particles in a carbon nanofiber framework using electrospinning and thermal annealing. The 1D carbon nanofiber structure provides an effective electronic conductive network and reduces the length of lithium-iondiffusion, which enhances the reactivity of the nanocomposite and improves electrode kinetics. Additionally, the carbon nanofiber framework isolates ultrafine In2O3 particles, preventing their aggregation. The small volume changes due to the ultrafine size of the In2O3 are buffered by the carbon materials, allowing the overall structure of the In2O3/C composite nanofiber to remain largely intact without crushing during charging and discharging cycles. This stability helps avoid electrode fracture and excessive SEI growth, resulting in superior cycle and rate performance compared with the pure In2O3 nanofiber electrodes.