Doping Strategy\nin Developing Ni-Rich Cathodes for\nHigh-Performance Lithium-Ion Batteries

Abstract

Doping is indispensable for ensuring\nthe long-term cycling stability\nof the Ni-rich layered cathodes. However, using a single type of dopant\nlimits the development of a stable, high-energy cathode material in\na single shot. In this study, a dual doping strategy using Al³⁺ and Nb⁵⁺ ions was adopted to improve the cycling\nstability of Li[Ni_0.92Co_0.04Mn_0.04]O₂ (NCM92) cathode; Al³⁺ doping fortifies\nthe crystal structure, while Nb⁵⁺ doping optimized the\nmorphology of the primary particles. The dual doping strategy not\nonly combines the benefits of both dopants simultaneously but also\ndemonstrates excellent performance enhancement through synergistic\neffects. The Li[Ni_0.905Co_0.04Mn_0.04Al_0.005Nb_0.01]O₂ (AlNb-NCM92) cathode,\nwhich was developed through the dual doping of Al and Nb, exhibited\nremarkable stability, retaining 88.3% of its initial capacity even\nafter 1000 cycles. This result suggests that the doping strategy needs\nto comprehensively consider both the crystal structure and the microstructure\nto maximize the long-term cycling stability of high-energy Ni-rich\ncathode materials.