▎ 摘　　要

To solve the problems of TiO2 electrode materials, such as short cycle life and intrinsic poor conductivity, N-doped modified graphene/mixed crystal phases TiO2 composites (TiO2/NRGO) have been prepared by microwave-assisted method. The numerous spherical hybrid anatase/rutile TiO2 nanoparticles evenly anchored on NRGO nanosheets and the TiO2 nanoparticles are approximately 20-50 nm. The ions/Na+ diffusion rate can be increased by the crystal interface effect of mixed crystal phases TiO2. In addition, the doping of nitrogen further improves the sodium storage properties of the composites. With this strategy, the as-prepared TiO2/NRGO composites deliver remarkable reversible capacities (223.3 mA h g(-1) at 0.1 A g(-1) over 50 cycles) and outstanding rate capability (101.1 mA h g(-1) at 2 A g(-1)) for Na-ion batteries (NIBs).