MXenes, as a new family of 2D materials, can be used as film electrodes in energy storage devices because of their hydrophilic surface, metallic conductivity, and rich surface chemistries. However, the poor ion transport of MXene film electrodes causes a great loss of surface reactivity, which significantly inhibits the full exploitation of the potential of MXene-based materials. To solve this issue, we report a facile electrolyte-induced self-assembly method to construct a 3D porous structure in the MXene-rGO hybrid film, which effectively facilitates rapid diffusion and transport of electrolyte ions in the film electrode while still maintaining high electrical conductivity. When the hybrid film is employed as electrode materials for lithium-ion batteries, it exhibits high specific capacity of 335.5 mA h g-1 at 0.05 A g-1 and good rate capability of 30% capacitance retention at 4 A g-1. Additionally, the film electrode exhibits excellent cycling stability without capacity decay after 1000 cycles under high rates (1 A g-1) owing to its stable structure. Furthermore, the electrochemical analysis also demonstrates that the novel 3D porous microstructure plays an important role in the fast reaction kinetics and high capacity of the MXene-rGO hybrid film electrode. This work may provide a new strategy to solve the issues related to poor ionic transport in MXene-based film electrodes.
Keywords: 3D porous structure; MXenes; MXene−rGO; film electrode; lithium-ion batteries; two-dimensional materials.