Nickel modified TiO2/C nanodisks with defective and near-amorphous structure for high-performance sodium-ion batteries

Low-cost sodium-ion batteries (SIBs) are the star products in grid-scale energy storage applications. Finding befitting anode materials is crucial to the advancement of SIBs. In this study, a novel two-dimension (2D) nanostructured anode material composed of TiO₂/C nanodisks and Ni nanoparticles that were synthesized by a facile metal-organic frameworks derived method is reported. By introducing divalent Ni²⁺ ions in the synthesis process, TiO₂/C microblocks were successfully transformed into the desirable 2D nanodisks, enabling the active materials to be more efficiently and fully utilized due to short diffusion path and substantive exposed active sites. Another important role of Ni²⁺ ions is as a doping source for TiO₂, resulting in the formation of a defective and near-amorphous TiO₂/C structure, which aids in improving the kinetics. In addition, some Ni nanoparticles formed and attached to the surface of the TiO₂/C nanodisks, which not only act as conductive bridges to make all the nanodisks electrically active but also act as pillars to prevent them from stacking. This unique 2D nanostructured anode material manifests high reversible capacities, excellent cycle performance, and impressive rate capability. This work provides a new means for the controllable synthesis of 2D nanostructured materials for energy storage applications.