Interface-Engineered Fe3O4/MXene Heterostructures for Enhanced Lithium-Ion Storage

Fe3O4 is a potential anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity (926 mAh g(-1)) and low cost, but its practical application is restricted by its low electrical conductivity and large volume changes during lithiation/delithiation. Herein, rationally designed Fe3O4/MXene hybrid heterostructures are constructed using an interfacial self-assembly approach that allows spontaneous deposition of Fe3O4 nanodots over Ti3C2Tx MXene nanosheets. The van der Waals-facilitated self-assembly process results in an ideal interfacial arrangement where Fe3O4 and MXene are in a complementary configuration. Among the different mass ratio arrangements, the self-assembled composite with 70 wt % Fe3O4 (Fe3O4/MXene-7) exhibits a much enhanced capacity of 782.7 mAh g(-1) at 0.1 A g(-1) after 100 cycles, which retains 667.9 mAh g(-1) at 1 A g(-1) after 600 cycles without any capacity decay. The devised anode could further maintain a reversible capacity of 279.1 mAh g(-1) when the current density reaches 5 A g(-1). Moreover, the charge storage capability of Fe3O4/MXene-7 is concluded to follow a dual-mode charge storage (battery capacitive) mechanism, which anticipates the constructed heterostructures promising future for next-generation LIBs.