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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.

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TiO 2 -coated Fe 2 O 3 composites exhibiting high electrochemical stability with oxygen defects were synthesized as the anode materials of Li-ion batteries using an easy sol−gel method. The industrial submicron-sized Fe 2 O 3 with no special shape and commercial tetrabutyl titanate were adopted as raw materials. The phase structures, morphologies, and elements distribution on the surface were characterized by X-ray diffraction analysis, electron paramagnetic resonance, scanning electron microscopy, X-ray photoelectron spectroscopy, and so forth. Results indicated that TiO 2 was well coated on the surface of raw Fe 2 O 3 with an average thickness of 5.5 nm, and the oxygen defects were successfully introduced into the composites with the reduction treatment. Electrochemical characterization indicated that TiO 2 coating was beneficial to the cycle performance of Fe 2 O 3 . The coating layer significantly improved the electronic conductivity and cycling stability of the Fe 2 O 3 anode material, as theoretically supported by the density functional theory calculation. Moreover, the introduction of oxygen defects in samples resulted in more excellent cycling stability compared to that in samples without reduction. The reduced Fe 2 O 3 @0.2TiO 2 sample exhibited a specific discharge capacity of 405.6 mA h•g −1 after 150 cycles, which effectively improved the intrinsic cycling performance of Fe 2 O 3 , and a corresponding discharge capacity of 50 mA h•g −1 after 30 cycles.

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