Preparation of carbon-coated Fe2 O3 @Ti3 C2 Tx composites by mussel-like modifications as high-performance anodes for lithium-ion batteries.

Abstract

Fe2 O3 with high theoretical capacity (1007 mA h g-1 ) and low cost is a potential anode material for lithium-ion batteries (LIBs), but its practical application is restricted by its low electrical conductivity and large volume changes during lithiation/delithiation. To solve these problems, Fe2 O3 @Ti3 C2 Tx composites were synthesized by a mussel-like modification method, which relies on the self-polymerization of dopamine under mild conditions. During polymerization, the electronegative group (-OH) on dopamine can easily coordinate with Fe3+ ions as well as form hydrogen bonds with the -OH terminal group on the surface of Ti3 C2 Tx , which induces a uniform distribution of Fe2 O3 on the Ti3 C2 Tx surface and mitigates self-accumulation of MXene nanosheets. In addition, the polydopamine-derived carbon layer protects Ti3 C2 Tx from oxidation during the hydrothermal process, which can further improve the electrical conductivity of the composites and buffer the volume expansion and particle agglomeration of Fe2 O3 . As a result, Fe2 O3 @Ti3 C2 Tx anodes exhibit ~100 % capacity retention with almost no capacity loss at 0.5 A g-1 after 250 cycles, and a stable capacity of 430 mA h g-1 at 2 A g-1 after 500 cycles. The unique structural design of this work provides new ideas for the development of MXene-based composites in energy storage applications.