The sol was homogenized and heated to 80 C under constant stirring to evaporate the excess water and to form the gel. The dried precursor was decomposed at 400 C (heating and cooling rate of 3 C/min) under Ar for 6 hours, followed by an intermediate hand grinding using a mortar and a pestle. After the intermediate grinding, an additional heat treatment at 700 C for 12 hours with a heating rate of 5 C /min was conducted under an Ar atmosphere to obtain the C-LFP.