ZnO/TiO2 dual-phase coating engineering on Ni-rich single-crystal NCM cathodes: Synergistic effects for structural integrity and long cycling stability

High-nickel single-crystal LiNi[Formula: see text]Co[Formula: see text]Mn[Formula: see text]O2 (SC-NCM811) cathode materials have attracted considerable attention in the field of lithium-ion batteries due to their superior cycling stability and capacity retention when compared to polycrystalline alternatives. However, several critical challenges remain in their commercialization, including increased lithium/nickel mixing, diminished ion diffusivity, irreversible phase transitions, and interfacial instability. These issues limit the performance and long-term stability of nickel-rich cathodes. In this work, we systematically investigate the structural and electrochemical properties of Ni-rich cathodes modified by solid-phase sintering, incorporating nanoscale ZnO and TiO2 dual coatings on the surface of the materials. The dual Zn/Ti coating effectively suppresses interfacial side reactions and reduces Li[Formula: see text]/Ni[Formula: see text] cation mixing, mitigating common issues related to cation disorder. Moreover, the introduction of strong M-O covalent bonds via ion doping during high-temperature sintering enhances the stability of the lattice structure, reinforcing the material’s integrity during cycling. Notably, the ZnTi-NCM sample exhibits a remarkable reversible capacity of 153.99 mAh⋅g[Formula: see text] after 200 cycles, with an impressively low inter-cycle capacity decay rate of only 0.073%, compared to 0.219% for the pristine SC-NCM. This significant improvement in cycling stability can be attributed to the synergistic effects of the Zn/Ti dual coating, which not only prevents detrimental interfacial reactions but also promotes lattice stabilization. This dual-modification strategy offers a promising avenue for the development of high-performance, durable cathode materials for next-generation lithium-ion batteries.