Synthesis and electrochemical performance of Na_(0.7)Fe_(0.7)Mn_(0.3)O_2 as a cathode material for Na-ion battery

摘要

A new technique was employed to synthesize Na_(0.7)Fe_(0.7)Mn_(0.3)O_2 precursor by adding citric acid to an aqueous solution of sodium, iron, and manganese salts. The rhombohedral Na_(0.7)Fe_(0.7)Mn_(0.3)O_2 was obtained by calcining the precursor in air. The precursor and its calcined products were characterized by X-ray powder diffraction and scanning electron microscopy. The results showed that a high-crystallized Na_(0.7)Fe_(0.7)Mn_(0.3)O_2 with a rhombohedral structure was obtained when the precursor was calcined over 600 °C in air for 8 h. The product obtained at 800 °C delivered a discharge capacity of about 130 mA h g~(-1) at the specific current of 13 mA g~(-1) in the 1st cycle between 1.5 V and 4.3 V.