The cathode of a lithium-ion secondary battery was fabricated using lithium iron phosphate blended with nano carbon black. The effects of four kinds of carbon black on lithium iron phosphate were evaluated by irreversible capacity loss and cyclingperformance. Analyses results show that the specimen 1B had the lowest irreversible capacity loss at charge-discharge cyclingrate 1C among all of the specimens to which 1 wt.% carbon black was added. All of the specimens had a lower chargedischargecapacity at cycling rate 1C and a higher charge-discharge capacity at cycling rate C/2. Cycling performance testresults indicated that the specimen 1B had the highest discharge-capacity and the lowest fade rate.

Keywords: Lithium iron phosphate, Carbon black, Capacity, Cycling performance