Abstract
Li2CoPO4F, a high-voltage cathode material which has high theoretical capacity of 287 mAh/g. This study used sol-gel method to synthesize LiCoPO4 and then used solid-state method to synthesize Li2CoPO4F with LiF, controlling the synthetical conditions of LiCoPO4 and Li2CoPO4F to explore the effects on electrochemical performance. First, we altered some experimental parameters of synthesizing LiCoPO4 in four series, including matrix composition, iron ion replacement, sintering temperature and whether coating xylooligosaccharide or not. Second, we altered some experimental parameters of synthesizing Li2CoPO4F in two series, including sintering temperature and time. In this study, among the first cycle discharge capacity of all, Li2CoPO4F made by 420 oC sintering LiCoPO4 has the highest value of 140 mAh/g；among the average discharge capacity of 1 ~ 15 cycles of all, Li2CoPO4F made by 500 oC sintering xylooligosaccharide-coated LiCoPO4 has the highest value of 89.5 mAh/g. The experimental results also indicate that 700 oC is the best sintering temperature, and the consequences are almost the same when sintering time varies in 1.5 ~ 12 hours at 700 oC.