High specific capacity O3-NaNi₁/₃Fe₁/₃Mn₁/₃O₂ cathode material for sodium-ion batteries

Abstract

Sodium-ion batteries (SIBs) have emerged as a promising alternative to lithium-ion batteries (LIBs) due to the abundance of sodium resources and lower material costs. O3-type layered oxides, particularly nickel‑manganese-based materials have a stable crystal structure. The preparation method of sodium-ion battery cathode materials is particularly crucial for their electrochemical performance. The conventional coprecipitation method imposes relatively stringent requirements regarding the concentrations of precipitants and complexing agents, as well as the inflow rate and pH control. Herein, the precursor of NaNi_1/3Fe_1/3Mn_1/3O₂ is prepared by the homogeneous co-precipitation, and the di-n-butylamine is used as the precipitant. Then O3-type NaNi₁_/₃Fe₁_/₃Mn₁_/₃O₂ cathode material is obtained at calcination temperatures ranging from 800 °C to 900 °C. The sample calcined at 850 °C, exhibits lower Mn³⁺ content, which effectively suppresses the Jahn-Teller effect. Electrochemical tests demonstrates that at 0.1C and 1.5–4.3 V the initial discharge capacity of NNFM-850 is 155.11 mAh/g. The initial discharge capacity of NNFM-850 at 1C is 105.09 mAh/g and retained 79.35 % capacity after 100 cycles.