Ultrahigh-Ni cobalt-free ternary cathode LiNi0.9Fe0.05Mn0.05O2: synthesis and electrochemical performance for high-energy density lithium-ion batteries

Abstract

Lithium-ion batteries are widely employed in diverse energy storage systems due to their high energy density and excellent cycling stability. However, most commercial cathode materials rely on cobalt (Co), a scarce and costly element, driving the urgent need for Co-free alternatives. Iron (Fe) provides cost-effectiveness and natural abundance, whereas manganese (Mn) usually serves as an electrochemically inert structural framework in cathode materials. The cathode material LiNi_0.9Fe_0.05Mn_0.05O₂ (NFM955) was synthesized by combining homogeneous co-precipitation and high-temperature solid-state methods. Its electrochemical performance was systematically evaluated through structural characterization and electrochemical measurements. The prepared NFM955 calcined at 725, 750, and 775 °C for 20 h exhibited initial discharge specific capacities of 194.35, 197.85, and 189.28 mAh g⁻¹ at 0.1C, with Coulombic efficiencies of 86.05%, 87.26%, and 86.59%, respectively. The specific capacities are 163.69, 167.60, and 162.99 mAh g⁻¹ and the capacity retention is 92.72%, 92.75%, and 87.77% after 100 cycles at 0.5C, respectively. The research results indicate that NFM955 provides a feasible strategy for the development of high-stability, Co-free ternary cathode materials.