Porous Na3V2(PO4)(3)/C as cathode material for high-rate sodium-ion batteries by sacrificed template method

摘要

NASICON-type Na3V2(PO4)(3)with a three-dimensional open framework structure has attracted wide attention, and it is regarded as one of the most promising cathode material for sodium-ion batteries. However, the low electronic conductivity restricts its charge-discharge capacity and electrochemical performance. With the purpose to solve this problem, polystyrene microspheres are applied in the preparation of cathode materials for sodium-ion batteries. Particular porous-structured Na3V2(PO4)(3)composing of interlaced nanosheets is obtained samples by a simple hydrothermal-assisted sol-gel method via a self-sacrificed template (polystyrene microsphere). As expected, the as-prepared porous sample delivers a reversible capacity of 109.2 mAh g(-1)at 0.2 C, an excellent rate performance (89.6 mAh g(-1)at 50 C) and superior cyclic stability (retention of 94% over 500 cycles at 50 C). The outstanding rate and cyclic performance are attributed to its unique porous structure which is conducive to improve electron conductivity and facilitate the diffusion of sodium ions.