Optimizing the Electrochemical Performance of Olivine LiMnxFe1–xPO4 Cathode Materials: Ongoing Progresses and Challenges

LiMnxFe1–xPO4 is the most promising olivine-type cathode material following LiFePO4 in terms of development potential. However, several technological challenges remain in its widespread application, particularly in terms of its low electronic conductivity, slow Li+ diffusion rate, and undetermined optimal Mn/Fe ratio. To date, enormous efforts have been devoted to addressing the intrinsic defects of LiMnxFe1–xPO4 to facilitate its electrochemical kinetics, and some companies have launched first-generation LiMnxFe1–xPO4. In this review, the structural characteristics, lithium storage mechanism, and synthesis methods of LiMnxFe1–xPO4 are first introduced. Wherein, a particular emphasis is placed on the rational design of precursors with tunable composition and tailored architecture, encompassing the Mn–Fe binary precursors and Mn–Fe–P ternary precursors. Then, up-to-date optimization strategies for improving the electrochemical performance of LiMnxFe1–xPO4, such as Mn/Fe ratio optimizing, conductive material compositing, element doping, and morphology controlling are discussed comprehensively, with a special focus on the regulation of additional discharge plateau, which not only prevents the decrease of energy density but also maintains the consistency of LiMnxFe1–xPO4 batteries. Finally, the critical issues, existing challenges, new research directions, and perspectives on further commercialization of LiMnxFe1–xPO4 are also discussed.