CO2 absorption and structural phase transition of .ALPHA.-LiFeO2

Abstract

α-LiFeO2 has been synthesized using Fe2O3 and LiNO3 under various conditions, and the relationship between the CO2 absorption ability and structural phase transition of the synthesized α-LiFeO2 has been investigated by X-ray diffraction (XRD) analysis and thermogravimetry and differential thermal analysis (TG-DTA). Mixed powders of Fe2O3 and LiNO3 were heated at 500°C for 5 h to synthesize α-LiFeO2. The CO2 absorption reaction of the synthesized α-LiFeO2 was performed in the temperature range from 200 to 500°C for 2 h under CO2 gas with a flow rate of 100 ml/min. It was found that the CO2 absorption ratio of the synthesized α-LiFeO2 increased with increasing temperature up to 400°C but markedly decreased above 425°C. XRD analysis clarified that α-LiFeO2 underwent structural phase transition at 425°C, indicating that the structural phase transition suppressed the CO2 absorption of α-LiFeO2. Results of the chemical composition analysis suggest that Li defects in LiFeO2 promote structural phase transition.