Boosting the Electrochemical Properties of LiNi_0.90Co_0.05Mn_0.05O₂ Cathode Materials via In Situ Constructed Li₃VO₄...

Nickel-rich cathode materials are widely valued for their high-energy-density and elevated voltage platform. Nevertheless, their limited cycling stability and rate performance significantly restrict their large-scale application in lithium-ion batteries. Herein, the electrochemical performance of LiNi_0.90Co_0.05Mn_0.05O₂ was enhanced by the in situ formation of a Li₃VO₄ coating layer on its surface. LiNi_0.90Co_0.05Mn_0.05O₂ was first synthesized by cofiring coprecipitated nickel-cobalt-manganese hydroxide precursor with LiOH·H₂O. Subsequently, a dense Li₃VO₄ modification layer was formed on the LiNi_0.90Co_0.05Mn_0.05O₂ surface via a wet chemical method. The modified cathode material exhibits an excellent rate performance (specific discharge capacity of 185.8 mAh·g^-1 at 10 C) and superior capacity retention (75.86% after 300 cycles at 2.7-4.5 V). The excellent electrochemical performance of the modified material is attributed to the in situ formation of Li₃VO₄ on its surface. This formation results in a dense protective layer and stabilizes the material structure. It also inhibits particle cracking, harmful rock-salt phase formation, and lattice distortion during cycling. This coating improves surface and interface properties, accelerates charge transfer kinetics, and reduces electrochemical polarization. This protective layer isolation of the electrode from direct electrolyte contact suppresses electrolyte decomposition and side reactions. Consequently, the Li₃VO₄ coating exerts synergistic effects, comprehensively enhancing cycling stability and rate capability. This method, based on the in situ growth of protective layers on the surface, provides an advanced and effective strategy for modifying cathode materials, offering valuable guidance for addressing structural and interfacial instability in other high-energy-density rechargeable batteries.