Preparing Li6V3(PO4)5 Cathode with Boron‐Doped Carbon Layer as a Cathode Material for Lithium‐Ion Batteries

Polyanionic cathode materials are increasingly used in research because of their good cycling performance, high theoretical capacity, and high operating voltage. However, it exhibits poor performance due to its structure, which prevents it from reaching its full theoretical capacity. In this study, carbon‐coated Li6V3(PO4)5@C cathode materials are constructed under Li3V2(PO4)3 research conditions using the sol–gel process and anhydrous citric acid as the carbon source. Several boron doping concentrations are investigated to create Li6V3(PO4)5@BC cathode materials. The electrochemical measurements demonstrate that during the first cycle, at a current density of 0.5 C and a B doping quantity of 2 wt%, the specific discharge capacity of Li6V3(PO4)5@BC reaches 167.43 mAh g−1. The steady discharge specific capacity following 80 cycles of constant‐current charging and discharging is 136.84 mAh g−1. Li6V3(PO4)5@BC‐2 has a specific discharge capacity of 131.1 mAh g−1 at 2 C. The material's electrochemical performance greatly improves following the right quantity of B doping, which is primarily attributed to the increase in carbon layer defects brought on by B's entrance. This can increase the rate of lithium‐ion migration and hold more lithium ions. The Li6V3(PO4)5@BC‐2 cathode material prepared by the sol‐gel method exhibits a high initial discharge specific capacity of 167.43 mAh g−1 at 0.5 C .