Rational synthesis of Cr0.5Nb24.5O62 microspheres as high-rate electrodes for lithium ion batteries.

Controllable fabrication of advanced electrode materials is critical for the development of lithium ion batteries (LIBs). Herein, for the first time, we report novel hierarchical porous chromium niobium oxide (Cr0.5Nb24.5O62) microspheres prepared by a facile one-step solvothermal method. The as-prepared Cr0.5Nb24.5O62 microspheres present 3D hierarchical porous structure consisting of cross-linked nanoparticles, high electronic conductivity and large specific surface area. Accordingly, the Cr0.5Nb24.5O62 microspheres show noticeable lithium ion storage performance with superior high-rate capability (199 mAh g-1 at 20C) and good cycling stability with a capacity retention of 95% over 1000 cycles, much better than the bulk Cr0.5Nb24.5O62 and TiNb24O62 counterparts. Our work demonstrates a new high-rate electrode material for high-power energy storage.