High-energy–density lithium manganese iron phosphate for lithium-ion batteries: Progresses, challenges, and prospects

The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries. Lithium manganese iron phosphate (LiMn_xFe_1-xPO₄) has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost, high safety, long cycle life, high voltage, good high-temperature performance, and high energy density. Although LiMn_xFe_1-xPO₄ has made significant breakthroughs in the past few decades, there are still facing great challenges in poor electronic conductivity and Li-ion diffusion, manganese dissolution affecting battery cycling performance, as well as low tap density. This review systematically summarizes the reaction mechanisms, various synthesis methods, and electrochemical properties of LiMn_xFe_1-xPO₄ to analyze reaction processes accurately and guide material preparation. Later, the main challenges currently faced are concluded, and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMn_xFe_1-xPO₄, including multi-scale particle regulation, heteroatom doping, surface coating, as well as microscopic morphology design. Finally, in view of the current research challenges faced by intrinsic reaction processes, kinetics, and energy storage applications, the promising research directions are anticipated. More importantly, it is expected to provide key insights into the development of high-performance and stable LiMn_xFe_1-xPO₄ materials, to achieve practical energy storage requirements.