NaV3O8/poly(3,4-ethylenedioxythiophene) composites as high-rate and long-lifespan cathode materials for reversible sodium storage

Sodium-ion batteries have received a surge of interests for the alternatives to lithium-ion batteries due to their abundant reserves and low cost. The quest of reliable and high-performance cathode materials is crucial to future Na storage technologies. Herein, poly(3,4-ethylenedioxythiophene) (PEDOT) was successfully introduced to NaV(3)O(8)via in situ oxidation polymerization, which can effectively enhance electron conductivity and ionic diffusion of NaV(3)O(8)material. As a result, these NaV3O8@PEDOT composites exhibit a significantly improved electrochemical performance including cycle stability and rate performance. In particular, NaV3O8@20 wt% PEDOT composite demonstrates better dispersibility and lower charge transfer resistance compared with bare NaV3O8, which delivers the first discharge capacity of 142 mAh center dot g(-1)and holds about 128.7 mAh center dot g(-1)after 300 cycles at a current density of 120 mA center dot g(-1). Even at a high current density of 300 mA center dot g(-1), a high reversible capacity of 99.6 mAh center dot g(-1)is revealed. All these consequences suggest that NaV3O8@20 wt% PEDOT composite may be a promising candidate to serve as a high-rate and long-lifespan cathode material for sodium-ion batteries.