Effect of Ru Doping on the Properties of LiFePO4/C Cathode Materials for Lithium-Ion Batteries

Abstract

Doping of metals is highly effective in improving electrochemical performance of lithium iron phosphate. Here, based on a first-principles calculation result that Ru doping at the Fe sites has positive effects on promoting the ability of electron and Li+ transmission by reducing the lattice parameter and band gap, as well as the increase in Fermi energy, we constructed Ru-doped LiFe1-xRuxPO4/C through the sol-gel preparation technology as cathode materials for Li-ion batteries. As a result, LFP-1 (x = 0.01) delivers excellent specific capacities of 162.6 and 110.6 mA h g-1 under 0.1 and 10 C, respectively. At the same time, LFP-1 emerges with excellent cycling performance, with a capacity retention of up to 95.6% after 300 cycles at 5 C. Ru doping is beneficial for improving the lithium diffusion coefficient and electrical conductivity, therefore strongly increasing electrochemical performance. This work represents a significant addition to exploring a new class of lithium iron phosphates with excellent performance in new energy storage and transition systems.