Abstract: 

     To improve the high-rate capacity and cycling stability of LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811), a facile strategy is proposed to fabricate tungsten/niobium (W/Nb) co-doped nickel-rich NCM811 cathodes with reinforced surface passivation and superior structural stability. Both the spinel-like phase on single W-doped cathode surface and the rock-salt phase on single Nb-doped cathode surface stabilize the material structure and retard side reactions with electrolyte. The co-doping optimizes lattice parameters and enhances Li⁺ diffusion channels besides suppresses the tremendous Li/Ni cation mixing of Nb-doping, which effectively promotes the embedding/de-embedding of Li⁺. The direct evolution from layered phase to rock-salt phase rather than the intermediate phase transition is brought about by W/Nb co-doping, while spinel phase is formed by W-doping. Notably, compared with single W-doping or single Nb-doping, W/Nb co-doping markedly reduces the total system energy, restrains anisotropic volume variation triggered by the H2↔H3 phase transition, stabilizes the bulk crystal structure, preserves particle integrity, and suppresses microcrack generation. The passivation layer constructed on particle surfaces via co-doping alleviates parasitic side reactions and further hinders microcrack initiation. Moreover, the synergistic effect between W and Nb effectively inhibits the formation of internal oxygen vacancies and surface Li₂CO₃ impurities. This strategy leveraging the synergism of high-valence cation co-doping can be extended as a simple and practical route to boost the electrochemical performance of nickel-rich layered cathodes for lithium-ion batteries under high cut-off voltages, offering new insights into the design of high-performance lithium-ion batteries based on ternary cathode materials.

Biography: 

    Wenzheng Zhou, PhD, serves as a Professor at the School of Physical Science and Technology, Guangxi University, and a recipient of the Outstanding Youth Fund of the Natural Science Foundation of Guangxi Zhuang Autonomous Region. He previously held multiple academic administrative posts, including Secretary-General of the Guangxi Physical Society, Deputy Director of the Central South Regional Working Committee under the University Physics Teaching Advisory Committee of the Ministry of Education, Member of the Central South Regional Working Committee under the Physics Major Teaching Advisory Committee of the Ministry of Education, and Member of the Physics Major Teaching Advisory Committee for Undergraduate Universities of Guangxi Zhuang Autonomous Region. Currently, he acts as a Standing Director of the National Electromagnetics Research Association of Institutions of Higher Education. His research focuses primarily on new energy materials and rechargeable secondary batteries, covering lithium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, and related systems. He has presided over numerous research projects funded by the National Natural Science Foundation of China, Natural Science Foundation of Guangxi Zhuang Autonomous Region, China Postdoctoral Science Foundation, and major local science and technology special programs. Dr. Zhou has published more than 170 papers in reputable domestic and international academic journals, with total citations of 3191 and an h-index of 31. He holds five authorized invention patents and has co-authored one textbook as the associate chief editor.