The mechanism of structural change in orthorhombic Li/LiFeO2 system on cycling

Abstract

Orrhorhombic LiFeO2 was synthesized at 150oC using a solid-state method. The Li/LiFeO2 cell presented not only a high initial capacity of over 150mAh/g, but also fairly good cycle retention of 73% after 50cycles within a voltage range between 1.5 and 4.5V. It was found that the orthorhombic phase of the LiFeO2 material underwent a structural change to the spinel LiFe5O8 phase during cycling. Especially it showed structural changes during the first chare/discharge process, which might be the main reason to induce the capacity loss of the Li/LiFeO2 system. We reported a new observation about the structural change mechanism of the orthorhombic Li/LiFeO2 cell during cycling using in-situ XRD and TEM analyses.