Thermal Stability of LiFePO4?-?Based Cathodes

The capacity and cyclability of solid-state synthesized laminate cells of type have been studied at 23, 40, and . Larger capacities were obtained for cells cycled at the elevated temperatures. No evidence was found of potentially troublesome reactions between the different components of the cells under charged and discharged conditions up to . Remanant X-ray diffraction peaks were observed from the delithiated phase for cells cycled at ambient temperature. Mossbauer spectroscopy showed different residual amounts of at the different temperatures: 22, 7, and 8% at 23, 40, and , respectively. The amount of residual was thus largest for cells cycled at room temperature, suggesting that slow kinetics hinder effective lithium insertion. (c)2000 The Electrochemical Society