Na-ion batteries are considered as next-generation battery technology in light of the abundant and low cost of sodium. Carbonophosphate compounds of Na3MPO4CO3 (M = Co/Ni) with a large theoretical capacity of 191 mAh/g were successfully synthesized by the hydrothermal method and their cathode properties were evaluated in Na-ion batteries for the first time. After high-speed ball milling with acetylene black at 400 rpm for 4 h, Na3CoPO4CO3 delivered a better initial capacity, 70 mAh/g. For Na3NiPO4CO3, electrochemical performance was not improved even after high-speed ball milling.
Keywords: Na-ion battery; Carbonophosphate; Hydrothermal method