LiMn0.8Fe0.2PO4@C cathode prepared via a novel hydrated MnHPO4 intermediate for high performance lithium-ion batteries

Abstract

With the rapid development of global electro-mobility and the impact of the Russian–Ukrainian war, the increasing cobalt and nickel prices have resulted in supply chain issues for the lithium-ion battery industry. Several types of cathode materials based on low-cost metals, such as manganese and iron, have been widely studied for lithium-ion batteries. Herein, a well-crystallized LiMn_0.8Fe_0.2PO₄@C cathode with a homogeneous structure is synthesized using hydrated MnHPO₄ as the precursor. Due to the synergistic effect of oxalic acid on the chelation and reduction of transition metals, a highly stable intermediate hydrated MnHPO₄ is constructed, which exhibits a similar structure to LiMnPO₄, further promoting the structural transformation from MnHPO₄ to LiMnPO₄. The obtained LiMn_0.8Fe_0.2PO₄@C exhibits a high electrical conductivity of 6.823 × 10⁻² S cm⁻¹ and excellent cycling stability with a capacity retention of 98.62% after 200 cycles. This work provides a scalable route for the design of low-cost and high-performance cathode materials for commercial lithium-ion batteries.