Enhancing storage performance of P2-type Na2/3Fe1/2Mn1/2O2 cathode materials by Al2O3 coating

The P2-type Na2/3Fe1/2Mn1/2O2 materials were synthesized by an ultrasonic spray pyrolysis followed by solid-state sintering method. The structures, morphologies and electrochemical performances of Na2/3Fe1/2Mn1/2O2 materials were characterized thoroughly by means of X-ray diffractometer, scanning electron microscope and electrochemical charge/discharge instruments. Moreover, a thin layer of Al2O3, which was formed on the surface of Na2/3Fe1/2Mn1/2O2, can enhance the storage performance by preventing the formation of Na2CO3·H2O, which is believed to enhance the electrochemical performances of Na2/3Fe1/2Mn1/2O2 materials. This facile surface modification method may pave a way to synthesize advanced cathode materials for sodium-ion batteries.