Innovative preparation of α-LiFeO2 using spent LiFePO4 and Na2CO3 by ball milling-assisted roasting–water leaching method

Abstract

α-LiFeO2 was successfully prepared using spent LiFePO4 and Na2CO3 by ball milling-assisted roasting–water leaching method. The effect of ball milling on roasting temperature was investigated by thermal analysis and X-ray diffraction (XRD) techniques. The effect of excess Na2CO3 on pure α-LiFeO2 synthesis was studied with the help of XRD techniques and scanning electron microscope (SEM). Results showed that ball milling pretreatment made α-LiFeO2 formation process shift towards lower roasting temperatures. Lithium iron oxides including α-LiFeO2 and Li0·5Fe2·5O4 could be obtained at 600 °C by ball milling, but 700 °C by hand grinding. With excess Na2CO3, more reaction channels provided by CO2 release and lower fusion temperature may accelerate the synthesis and grain refinement of α-LiFeO2. Pure α-LiFeO2 could be obtained with a molar ratio of 1:1.8 between LiFePO4 and Na2CO3 at 600 °C for 3 h. A new approach was provided for preparing α-LiFeO2 from spent LiFePO4 by roasting with dephosphorization agent Na2CO3.