Interface-Enhanced Li+ Transport in 3D Surface-Engineered Mesoporous Carbon/Fe2O3 Nanocomposites for High-Performance Lithium−Ion Battery Anodes

Abstract

The rapid growth of hybrid electric vehicles and smart grids has intensified the demand for lithium−ion batteries (LIBs) with high energy densities and long cycle life, whereas the relatively low theoretical capacity of graphite limits further improvements in cell-level energy density. Transition metal oxides, particularly Fe2O3, suffer from poor electrical conductivity and severe volume variations during multielectron conversion reactions, severely hindering their practical application. Herein, a sequential strategy involving F127/TMB-directed mesoporous polydopamine sphere formation followed by CTAB-assisted Fe-species post-loading was developed to prepare a three-dimensional mesoporous carbon/Fe2O3 (MC-Fe2O3) composite anode. In this structure, Fe2O3 nanoparticles are anchored on the surface and within the accessible mesopores of an interconnected mesoporous carbon sphere framework. This architecture shortens Li+ diffusion pathways and helps buffer volume changes during cycling. As a result, the MC-Fe2O3 anode delivers a reversible capacity of 1175 mAh g−1 at 0.1 A g−1 and 780.8 mAh g−1 at 1.0 A g−1, with good rate capability and long-term cycling stability. These results suggest that the surface-engineered 3D MC-Fe2O3 composite is a promising high-capacity anode material for LIBs.