Modification of LiNi_0.6Co_0.2Mn_0.2O₂ Cathode Materials via Boron Element-Doping for Lithium-ion Batteries

Boron (B)-doped LiNi_0.6Co_0.2Mn_0.2O₂ cathode materials were prepared by oxalate co-precipitation and subsequent heat treatment. The effects of doping with different boron sources (B₂O₃, H₃BO₃ and LiBO₂) on the morphology, structure and electrochemical properties of the materials were investigated. The X-ray diffracation and Rietveld refinement revealed that the B element was successfully doped into the material lattice. The electrochemical performance characterization showed that the doping effect of B₂O₃ was the best, with excellent rate performance (the specific discharge capacity was 145.1 mA·h/g at 5 C) and long-term cycle stability (the capacity retention ratio was 84.5% after 300 cycles at 1 C). The enhanced electrochemical performance is attributed to the fact that boron doping effectively reduces the surface residual lithium compound, enhances the structural stability of the material, effectively inhibits the voltage drop and improve the polarization phenomenon, and reduces the charge transfer resistance, thus inhibiting the capacity decay and achieving excellent electrochemical performance.