A Promising Corrosion Engineering-based Strategy for Green Synthesis of LiMnxFe1-xPO4 Cathode for Lithium-ion Batteries

Abstract

LiMnxFe1-xPO4 cathode material, which demonstrates higher energy density compared to LiFePO4 along with unique physicochemical properties, has attracted extensive research attention for high-performance lithium-ion batteries (LIBs). However, conventional synthesis methods for LiMnxFe1-xPO4 suffer from low atomic utilization efficiency and complicated technical processes, which are undesirable for practical implementation. Herein, we propose an innovative corrosion engineering-based strategy utilizing metallic manganese and iron as metal sources to fabricate LiMnxFe1-xPO4 with enhanced atom economy. Thermodynamic analysis combined with experimental verification confirms the complete corrosion reaction of metallic Mn and Fe in the M-NH4+-H2O system. This approach satisfies green chemistry requirements through recyclability of the ammonium solution. While simultaneous corrosion of Mn and Fe maintains phase composition integrity, it induces morphological evolution of MnOx from nanorods to nanoparticles. Electrochemical evaluations reveal that LiMn0.6Fe0.4PO4 exhibits optimized kinetic characteristics compared to LiMn0.7Fe0.3PO4 and LiMn0.5Fe0.5PO4 counterparts, delivering exceptional lithium storage performances with 118 mAh g-1 at 10 C and remarkable cyclability (99.0% capacity retention after 400 cycles at 2 C). This breakthrough in sustainable synthesis paves the way for cost-effective production of high-performance LiMnxFe1-xPO4 with both environmental and economic benefits.