Recent Progress in Capacity Enhancement of LiFePO4 Cathode for Li-Ion Batteries

LiFePO4 (lithium iron phosphate (LFP)) is a promising cathode material due to its environmental friendliness, high cycling performance, and safety characteristics. On the basis of these advantages, many efforts have been devoted to increasing specific capacity and high-rate capacity to satisfy the requirement for next-generation batteries with higher energy density. However, the improvement of LFP capacity is mainly affected by dynamic factors such as low Li-ion diffusion coefficient and poor electrical conductivity. The electrical conductivity and the diffusion of lithium ions can be enhanced by using novel strategies such as surface modification, particle size reduction, and lattice substitution (doping), all of which lead to improved electrochemical performance. In addition, cathode prelithiation additives have been proved to be quite effective in improving initial capacity for full cell application. The aim of this review paper is to summarize the strategies of capacity enhancement, to discuss the effect of the cathode prelithiation additives on specific capacity, and to analyze how the features of LFP (including its structure and phase transformation reaction) influence electrochemical properties. Based on this literature data analysis, we gain an insight into capacity-enhancement strategies and provide perspectives for the further capacity development of LFP cathode material.