Activation of LiCoPO₄ in Air

LiCoPO₄ was synthesized in a short time by a microwave-assisted solvothermal technique at 220°C. The as-prepared samples are characterized as belonging to the Pn21a symmetry group, having poor electrochemical performance, and low specific capacity around 30 mAh/g. Further, activation at 700°C under air and argon increased the specific capacity to 57 mAh/g and 55 mAh/g, respectively. The local atomic and electronic structure of the samples before and after annealing was studied using x-ray absorption spectroscopy (XAS). The activation under air and Ar led to a phase transition from the Pn21a space group to the Pnma space group without changes in the Co oxidation state. Therefore, using myristic acid as a source for carbon coating, we found that there were no specific requirements for the activation atmosphere.