Dual Modification of Olivine LiFe0.5Mn0.5PO4 Cathodes with Accelerated Kinetics for High-Rate Lithium-Ion Batteries

Developing olivine-type lithium ferromanganese phosphates with high ionic/electronic conductivity is vital to promote their practical application in long-life and high-rate lithium-ion batteries (LIBs). Herein, we propose a dual modification strategy combining C-coating and Nb-doping and apply it to enhance LiFe0.5Mn0.5PO4 cathode materials. The uniform and compact C-coating layer successfully fabricates the high-speed conductive network among primary particles and meantime prevents the attack of electrolytes. The strong Nb-O coordination can effectively accelerate ion diffusion and electron transport within the nanoparticles while suppressing the Jahn-Teller effect of Mn3+. The dual modifications synergistically improve the LiFe0.5Mn0.5PO4 cathode materials with superior lithium-storage capacities of 152 and 115 mAh g-1 at 0.1 and 5 C, respectively. Furthermore, it exhibits an impressive cycling performance with an ultrahigh capacity retention of 95.4% after 1000 cycles at 1 C. These findings extend the application of surface-to-bulk co-modification in developing novel cathode materials used in high-performance LIBs.

Automated summary

In this study, a dual modification strategy of C-coating and Nb-doping was proposed and applied to improve LiFe0.5Mn0.5PO4 cathode materials. The C-coating layer formed a high-speed conductive network and provided protection to the electrolytes. The Nb-O coordination accelerated ion diffusion and electron transport, while suppressing the Jahn-Teller effect of Mn3+. The dual modifications resulted in LiFe0.5Mn0.5PO4 cathode materials with enhanced lithium-storage capacities and impressive cycling performance.