High valence tungsten doping enhances the lithium storage performance of high-voltage medium-nickel low-cobalt layered oxide cathode

High voltage and low cobalt lithium oxide cathode materials are regarded as promising candidates for high energy density lithium-ion batteries due to their excellent attributes of high capacity and cost-effectiveness. However, increasing the charging cut-off voltage and reducing cobalt content would result in the degradation of the electrode-electrolyte interface environment and other bulk phase layered structure issues, which can significantly impact the service life of the battery. In this study, we successfully synthesized W-doped LiNi0.65Co0.05Mn0.30O2 cathode material by introducing a small amount (1 mol%) of tungsten (W) during the stage of precursor lithiation annealing. The introduction of W doping has shown remarkable enhancements in cyclic stability (capacity retention rate for 200 cycles: 97 % vs. 89 %) than pristine material at 4.5 V. Moreover, the prepared graphite-type high-voltage full battery also exhibits a capacity retention rate of 90.2 % after 200 cycles and has a high energy density of up to 258 Wh kg-1. These improvements can be attributed to the high valence (+6) W doping passivating the activity of the cathode material, thereby enhancing the bulk structure and electrode-electrolyte interface stability of the material. These findings provide valuable strategic insights for utilizing high-voltage and low-cobalt cathode materials in lithium-ion batteries.