Novel MXene-based hierarchically porous composite as superior electrodes for Li-ion storage

Abstract

MXenes are widely investigated for electrochemical energy storage, sensors, and other fields, because of their excellent electrical conductivity and rapid ion transport. Nevertheless, the electrochemical properties and structural stability of MXenes are greatly restricted by the inherent self-restacking. Here we design and synthesize a series of hierarchically porous composites (C-Fe3O4/Ti3C2), where carbon-coated Fe3O4 (C-Fe3O4) acts as buttress to support the few-layered Ti3C2 MXene (f-Ti3C2) based on the hydrogen bonding interaction and Van der Waals force between the carbon coating layer and the f-Ti3C2. The self-restacking of f-Ti3C2 MXene and the sluggish reaction kinetics of Fe3O4 can be improved simultaneously when the C-Fe3O4/Ti3C2 composites are applied as anode for lithium-ion storage. The C-Fe3O4/Ti3C2 1:1 anode maintains ultrahigh reversible capacity of 1150 mAh g−1 at 1 A g−1 even after 1000 deep cycles, and 561 mAh g−1 at 5 A g−1, 340 mAh g−1 at 7 A g−1, showing excellent lithium-ion storage performance and superior structural stability that originated from the synergistic interaction between Fe3O4 and f-Ti3C2 MXene. The hierarchically porous composite opens up new possibilities in designing 2D MXene-based composites for catalytic, sensing, biomedical, energy storage materials.