China Nonferrous Metallurgy

Sodium hexafluoroferrate can be used as a cathode material for lithium-ion batteries and sodium-ion batteries due to its strong storage capacity of lithium ions and sodium ions, with such shortages as long technological process, toxic harmful or low-solubility raw materials, poor electrochemical properties. Therefore, a novel method using Na₃Fe(C₂O4)₃ as an intermediate is proposed to synthesize sodium hexafluoroferrate material. The results show that the material prepared at 700℃ for 7h in N₂ atmosphere exhibits excellent electrochemical properties, with the second discharge specific capacity of 229.1mAh/g and the capacity retention of 97.9% after 100 cycles for lithium-ion batteries, the first discharge specific capacity of 138mAh/g and the capacity retention of 90% after 100 cycles for sodium-ion batteries. This route is fairly suitable for industrial production owing to its environmental friendliness, short technological process, low production cost and good product performance.