Chemically-confined mesoporous γ-Fe2O3 nanospheres with Ti3C2Tx MXene via alkali treatment for enhanced lithium storage

Abstract

Developing Fe2O3-based anode materials with high electrical conductivity and structure stability is crucial for high-performance lithium-ion batteries (LIBs). Herein, we design a MXene-confined mesoporous γ-Fe2O3 nanosphere architecture via the in-situ formation of hydrogen bonds under alkali treatment. The mesoporous γ-Fe2O3 nanosphere consisting of nanocrystalline subunits is wrapped by Ti3C2Tx MXene, which acting as the shield can effectively mitigate the volume change of γ-Fe2O3 nanosphere and guarantee a fast electron flow. The distinctive porous structure of as-prepared γ-Fe2O3@Ti3C2Tx electrode can provide a large electrode-electrolyte interface and accessibility of active sites to accelerate the electrochemical activity. With the assistance of hydrogen bonds, the structural and interfacial stabilities of γ-Fe2O3@Ti3C2Tx can be obviously enhanced, leading to a connected conductive-network to facilitate the diffusion kinetics and cycle stability. The galvanostatic intermittent titration technique (GITT) analysis further confirms the Li+ diffusion coefficient (DGITT) of γ-Fe2O3@Ti3C2Tx composite by alkali treatment are improved. As a consequence, the obtained γ-Fe2O3@Ti3C2Tx anode for LIBs delivers an ultrahigh reversible capacity of 1060 mA h g−1 at 0.5 A g−1 after 400 cycles and an excellent long-term stability without obvious capacity loss (466 mA h g−1 after 800 cycles at 2 A g−1).