Pseudocapacitive Li+ intercalation in porous Ti2Nb10O29 nanospheres enables ultra-fast lithium storage

Owing to the multiple redox couples, Ti2Nb10O29 has a high theoretical capacity and exhibits enormous potential as an alternative anode material for Li4Ti5O12. Herein, porous Ti2Nb10O29 hierarchical nanospheres are prepared with the assistance of block copolymer F127 via a facile one-pot solvothermal method. Such porous Ti2Nb10O29 nanospheres, with diameters of 300–500 nm, are composed of primary nanoparticles and exhibit a BET surface area of 19.43 m2 g−1 with concentrated pore sizes of approximate 10.5 nm. As anode materials, the Ti2Nb10O29 nanospheres display high reversible capacity of 247.8 mA h g−1 at 1 C, and excellent rate capabilities of 149.6 mA h g−1 at 20 C and 94.9 mA h g−1 at 50 C, which obviously surpasses previously reported performance on Ti2Nb10O29 materials. During long-term cycles, the Ti2Nb10O29 electrodes present a high reversible capacity of 141.6 mA h g−1 after 1000 cycles at 10 C, corresponding to a capacity retention ratio of almost 100%. Furthermore, the kinetic information obtained from cyclic voltammetry indicates that the pseudocapacitive effects play an important role in the rate capability and cycling stablility. These results demonstrate the great potential of Ti2Nb10O29 as a practical anode material for high-rate and long-life lithium-ion batteries.