Spatially confined synthesis of TiNb2O7 quantum dots onto mesoporous carbon and Ti3C2TX MXene for boosting lithium storage

TiNb2O7 has been emerged as one of the most promising electrode materials for high-energy lithium-ion batteries. However, limited by the slow electron/ion transport kinetics, and insufficient active sites in the bulk structure, the TiNb2O7 electrode still suffers from unsatisfactory lithium storage performance. Herein, we demonstrate a spatially confined strategy toward a novel TiNb2O7-NMC/MXene composite through a triblock copolymer-directed one-pot solvothermal route, where TiNb2O7 quantum dots with a particle size of 2-3 nm are evenly embedded into N-doped mesoporous carbon (NMC) and Ti3C2TX MXene. Impressively, the as-prepared TiNb2O7-NMC/MXene anode exhibits a high reversible capacity (486.2 mAh g-1 at 0.1 A g-1 after 100 cycles) and long cycle lifespan (363.4 mAh g-1 at 1 A g-1 after 500 cycles). Both experimental and theorical results further demonstrate that such a superior lithium storage performance is mainly ascribed to the synergistic effect among 0D TiNb2O7 quantum dots, 2D Ti3C2TX MXene nanosheets, and N-doped mesoporous carbon. The strategy presented also opens up new horizon for space-confined preparation of high-performance electrode materials.