A β-FeOOH/MXene sandwich for high-performance anodes in lithium-ion batteries.

FeOOH is one of the earth abundant and high-capacity anode materials for lithium-ion batteries (LIBs), but faces problems of inevitable structure collapse and thus poor capacity retention. Herein, we report a composite of β-FeOOH/TiCT MXene sandwich by an intercalation of β-FeOOH nanorods within single-layer TiCT MXene flakes. After 100 cycles, the β-FeOOH/TiCT composite retains a capacity of 937.5 mA h g at 200 mA g, and 671.4 mA h g at 1 A g. The composite as an anode in LIB delivers improved cyclability and better high-rate performance compared to pristine β-FeOOH, which result from the excellent conductivity of single-layer MXene, facilitating mass transport by the sandwich structure. This work provides a strategy for the design of electrodes, particularly in Na-ion and K-ion batteries, which involve active materials that experience volume change and structural damage during cycling.