LiFePO₄ (lithium iron phosphate, abbreviated as 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 employing novel strategies such as surface modification, particle size-reduction, and lattice substitution (doping), all of which lead to improved electrochemical performance. In addition, cathode pre-lithiation 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 pre-lithiation 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.

An industrial submicron-sized Fe₂O₃ with no special shape was decorated by a multi-layer coating of oxygen-deficient TiO_2−x and conducting polymer PEDOT (poly 3,4-ethylenedioxythiophene). A facile sol–gel method followed by an EDOT polymerization process was adopted to synthesize the hierarchical coating composite. The microstructure and phase composition were characterized using an X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). In particular, the existence state of PEDOT was determined using Fourier transform infrared (FT-IR) and a thermogravimetric (TG) analysis. The characterization results indicated the dual phase was well-coated on the Fe₂O₃ and its thickness was nano scale. Electrochemical characterization indicated that the multi-layer coating was helpful for significantly enhancing the cycle stability of the Fe₂O₃, and its electrochemical performance was even better than that of the single-layer coating samples. The synergistic effects of the ceramic phase and conducting polymer were demonstrated to be useful for improving electrochemical properties. The obtained FTP-24 sample exhibited a specific discharge capacity of 588.9 mAh/g after 360 cycles at a current density of 100 mA/g, which effectively improved the intrinsic cycling performance of the Fe₂O₃, with a corresponding discharge capacity of 50 mAh/g after 30 cycles.