Modification And Electrochemical Performance Of Na₂C₆O₆ As Cathode Material Of Sodium-Ion Batteries

Na⁺not only has a similar electrochemical potential as Li⁺,but also has the advantages of low cost and abundant earth reserves,which makes sodium-ion batteries?SIBs?becoming a promising energy storage technology.Among cathode materials of SIBs,organic compounds such as carbonyl compounds have gained a lot of attention due to high theoretical specific capacity,rich diversity,and recyclable characteristics.But organic electrode materials also have disadvantages such as poor conductivity and easily soluble in electrolytes.Na₂C₆O₆ is one of the current organic cathode materials for sodium-ion batteries.Although it has a high theoretical specific capacity,self-pulverizes leads to a decrease in reversible specific capacity during the electrochemical cycle.At the same time,poor conductivity of Na₂C₆O₆ also limits its electrochemical performance at high current density.In this paper,Na₂C₆O₆ is used as the organic cathode material for SIBs.Na₂C₆O₆-PANI are prepared by compounding with conductive polyaniline?PANI?and Na₂C₆O₆/RGO-SA are prepared by compounding with reduced graphene oxide-sodium alginate gel?RGO-SA?,which can improve the capacity attenuation of Na₂C₆O₆ which caused by poor conductivity at high current density.The SEM,TEM,XRD,and FT-IR have been used to demonstrate that these materials can improve the electrochemical performance of Na₂C₆O₆ as a positive electrode material for SIBs without changing the structure of Na₂C₆O₆.According to the electrochemical performance test,at a current density of 500 mA/g,the specific discharge capacity of the Na₂C₆O₆-PANI drops to 174mAh/g from 330 mAh/g after 50 cycles and the Na₂C₆O₆/RGO-SA drops to 157 mAh/g from 370 mAh/g after 100 cycles.After 500 cycles at a high current density of 1000mA/g,the discharge specific capacity of Na₂C₆O₆/RGO-SA was 137 mAh/g.The composites have good electrochemical performance under high current density.The research results in this paper show that both Na₂C₆O₆-PANI and Na₂C₆O₆/RGO-SA prepared by doping method can effectively improve the electrochemical performance of Na₂C₆O₆.It shows that improving the conductivity of Na₂C₆O₆ can ameliorate the electrochemical performance of the material at high current density.