Effect of fast heating and cooling in the hydrothermal synthesis on LiFePO4 microparticles

Abstract

Hydrothermal synthesis is a chemical process that has gained much interest in recent years, especially for the synthesis of LiFePO4 since it is a method that requires a relatively low temperature, short reaction time, and it is reproducible. In this work, LiFePO4 microparticles have been synthesized by means of a fast heating system (sand bath) under hydrothermal conditions. The experiments have been carried out under two different heating rates (86 °C/min and 5.26 °C/min), two different residence times (5 and 30 min), and two different cooling rates (−455 °C/min and −8 °C/min). The effects that these three parameters had on the synthesized particles were verified using several techniques such as X-ray diffraction and scanning electron microscopy. It was observed that the heating rate had a great influence on the purity, crystallization, and morphology of the synthesized LiFePO4 particles. In addition, the high influence of cooling rate on the crystallization and morphology of the particles was also analyzed.