Collaboratively enhancing electrochemical properties of LiNi0.83Co0.11Mn0.06O2 through doping and coating of quadrivalent elements

Ni-rich layered oxides (Ni >= 80%) with high energy density have become a mainstream cathode material for Li-ion batteries. However, irreversible phase transitions and interface instability are deep-seated challenges in commercializing Ni-rich materials. This study used a collaborative modification strategy involving doping and coating with quadrivalent elements to construct Ni-rich materials. In particular, introducing tetravalent Zr makes the valence change of Ni (2+ to 4+) more accessible to complete spontaneously during the charging and discharging processes, which significantly suppresses the cationic mixing and irreversible phase transition (H2 <-> H3). Combining the strategy of constructing CeO2 coatings on the surface and interfacial spinel-like phases improves the Li+ diffusion kinetics and interfacial stability. Simultaneously, part of the strongly oxidizing four-valence Ce4+ diffuses to the surface layer, further increasing the average valence state of Ni. Therefore, LiNi0.83Co0.11Mn0.06O2 (NCM)-Zr@Ce achieves 78.5% outstanding retention at 1.0C after 200 cycles within 3.0-4.3 V compared to unmodified NCM with 41.4% retention. The improved cyclic stability can be attributed to the collaborative modification strategy of the quadrivalent elements, which provides an effective synergistic modification strategy for developing high-performance Li-ion battery cathode materials.