Controllable charge capacity using a black additive for high-energy-density sodium-ion batteries

摘要: Sodium-deficient P2 or P′2 type layered materials are known to deliver high capacity with acceptable retention. However, the initial charge is substantially lower than discharge because of insufficient amount sodium in their crystal structure, hindering practical application these as cathodes sodium-ion batteries (SIBs). This limitation can be overcome by introducing a sacrificial salt additive, which participates electrochemical oxidation reaction releasing enough ions compensate for content cathode material. Herein, NaNO2 was blended high-capacity orthorhombic Na2/3[Co0.05Mn0.95]O2 material, increasing from 154 210 mA h g−1. During oxidation, oxidatively decomposed following reaction: → NO2 + Na+ e−, where an oxidizer that enables full desodiation Na0[Co0.05Mn0.95]O2. The first coulombic efficiency improved 1.38 0.98 virtue sacrificing and oxidizing roles NaNO2. These findings demonstrate introduction additional source open new opportunities adoption sodium-deficient SIBs.