Characteristics of LiFePO4 obtained through a one step continuous hydrothermal synthesis process working in supercritical water

The olivine-like material LiFePO₄ was prepared via a continuous hydrothermal synthesis process working from subcritical to supercritical water conditions. The influence of some processing parameters–temperature and reaction time–was investigated in terms of material purity, grain size and morphology. Supercritical conditions were found to be attractive to synthesize in one step a well-crystallized material without impurities. The primary particles size was in the nanometric range. They showed a natural tendency to form micron size agglomerates, which were supposed to be the cause of the limited capacity, as demonstrated through a cross study using laser particle size distribution analysis, electrochemical measurements and XRD at different Li contents.