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

摘要

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 NaV3O8 via in situ oxidation polymerization,which can effectively enhance electron conductivity and ionic diffusion of NaV3O8 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-g-1and holds about 128.7 mAh·g-1 after 300 cycles at a current density of 120 mA·g-1.Even at a high current density of 300 mA·g-1,a high reversible capacity of 99.6 mAh·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.