Iron phosphide stabilization strategy enables long-cycling Co-free lithium-rich manganese-based cathode materials

Co-free lithium-rich manganese-based oxides (LRMOs), which offer energy densities over 1000 Wh kg-1 and low raw material cost, are attractive cathode candidates for next generation energy density lithium-ion batteries (LIBs). Nonetheless, their practical application is hindered by their high initial irreversible capacity loss, capacity and voltage decay and voltage hysteresis. Herein, a novel iron phosphide modification strategy is presented, where Fe3P is incorporated into the bulk phase of the Li1.2Ni0.2Mn0.6O2 (LNMO) cathode material during the fabrication process of high-temperature calcination of the precursor after spray drying. This regulation stabilizes the crystal lattice of LNMO, promotes the formation of a robust cathode-electrolyte interphase (CEI), and mitigates decomposition of the electrolyte, thereby significantly enhancing the cycling stability and rate capability. Consequently, the modified LNMO achieves a capacity of 179 mAh g-1 (98% capacity retention) after 450 cycles at 1C, and 82% capacity retention even after 1,000 cycles at 5C. The regulatory strategy is facile and straightforward yet demonstrates superior electrochemical stability, which has potential for wide-ranging applications.