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Nano-crystalline LiFeO2 has been synthesized at low temperature (150 °C) using the solid-state method. It was composed of orthorhombic LiFeO2 and a small amount of spinel LiFe5O8 phases. A Li/LiFeO2 cell showed not only a fairly high initial discharge capacity of over 150 mAh/g, but also a good cycle retention rate at room temperature. We first found that the orthorhombic LiFeO2 underwent a structural change to the spinel phase (LiFe5O8) during the charge/discharge process, which resulted in the capacity decline of the Li/LiFeO2 system. [Copyright &y& Elsevier]

Orthorhombic LiFeO2 was synthesized at low temperature (150 °C) using a solid-state method. The Li/LiFeO2 cell presented not only a high initial capacity of over 150 mAh/g, but also fairly good cycle retention of 73% after 50 cycles within a voltage range between 1.5 and 4.5 V. It was found that the orthorhombic phase of the LiFeO2 material underwent a structural change to the spinel phase during cycling. Especially it showed severe structural changes during the first charge/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. [Copyright &y& Elsevier]