Lithium manganese iron phosphate (LiMn_1-yFe_yPO₄) rechargeable batteries: bridging material innovation with practical cell design

The growing demand for high-energy storage, rapid power delivery, and excellent safety in contemporary Li-ion rechargeable batteries (LIBs) has driven extensive research into lithium manganese iron phosphates (LiMn_1-yFe_yPO₄, LMFP) as promising cathode materials. The strong P–O covalent bonds in the olivine structure of LMFP ensure exceptional thermal and structural stability compared to conventional layered LiNi_1-y-zCo_yMn_zO₂ (NCM). In addition, the relatively low energy density of LiFePO₄ (LFP), which is isostructural to LMFP, has been significantly increased by the incorporation of Mn redox reactions with a strong reducing tendency. This widespread recognition has advanced our understanding of the physicochemical characteristics of LMFP, which are closely related to its chemical compositions, particle morphology, synthesis processes, and cycling conditions. Despite notable progress in improving the structural integrity and electrochemical superiority of LMFP, most academic research has focused on LMFP/Li metal half-cell systems. However, practical applications of LIBs require more intricate system configurations involving non-Li anode materials, such as graphite and Li₄Ti₅O₁₂ (LTO). This comprehensive review explores key electrochemical phenomena in LMFP/graphite and LMFP/LTO full cells under both standard and elevated temperatures. Additionally, it offers insights into optimal cell design strategies and practical technologies aimed at achieving a well-balanced combination of energy density, thermal stability, and cost-effectiveness. These advancements position LMFP-based rechargeable batteries as a promising solution for next-generation energy storage systems.