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/Ti₃C₂T_x MXene sandwich by an intercalation of β-FeOOH nanorods within single-layer Ti₃C₂T_x MXene flakes. After 100 cycles, the β-FeOOH/Ti₃C₂T_x composite retains a capacity of 937.5 mA h g^-1 at 200 mA g^-1, and 671.4 mA h g^-1 at 1 A g^-1. 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.