Improving the Performance of LiNi 0.925 Co 0.065 Mn 0.01 O 2 via Ti 4+ & Nb 5+ Co-Modifications.

Ni-rich layer-structured materials are some of the most promising cathodes owing to their attractive reversible capacity and cost-effectiveness. When the Ni content is increased to 90% and higher, mechanical deterioration becomes serious and leads to accelerated cyclic degradation, since removable Li + is ∼0.85, accompanied by large lattice variation during operation. Here, we investigate the influences of Ti 4+ bulky substitution, Nb 5+ surface treatment, and their coutilization on the behavior of LiNi 0.925 Co 0.065 Mn 0.01 O 2 (NCM92). In contrast to the limited positive effects of monousage, the coutilization of Ti 4+ and Nb 5+ obviously suppresses particles' pulverization, relying on their synergistic effects of the shape of lattice variation and the protection of a tough shell layer. As a result, Ti & Nb-LiNi 0.925 Co 0.065 Mn 0.01 O 2 (TiNb-NCM92) presents the best capacity retention, as high as 90.2% after 300 cycles, much higher than NCM92 (49.0%), Ti-NCM92 (76.3%), and Nb-NCM92 (72.4%). Our approaches demonstrate that the serious mechanical challenges of ultrahigh nickel cathodes could be alleviated by various remedies coutilized together.