Intercalation mechanisms of lithium into graphitized needle cokes

A needle coke was graphitized at different heat treatment temperature (2 000℃ to 3 000℃). The electrochemical intercalation mechanism of Li into the graphitized coke has been studied in Li|1 mol·L 1 LiClO 4+ethylene carbonate/diethylene carbonate|graphite cells, using an in situ X Ray diffraction (XRD) technique.The study of Li C intercalation processes of the graphitized coke reveals that there are three major types of intercalation behavior.The first is uniformly intercalated at all Li C compounds in graphitized coke heated at 2 250℃;the second is obviously staging phenomenon during intercalation for the graphitized coke heated at 2 750℃; the third is cointercalation of solvated Li ion at high potential (>0.3V) and then lithium electrochemical intercalation at lower potential for that heated at 3 000℃, resulting in the decrease of capacity and efficiency of graphite negative electrode for lithium ion secondary battery.

A needle coke was graphitized at different heat treatment temperature (2000 degreesC to 3000 degreesC).The electrochemical intercalation mechanism of Li into the graphitized coke has been studied in Li \1 mol.L(-1) LiClO(4) + ethylene carbonate/diethylene carbonate I graphite cells, using an in-situ X-Ray diffraction (XRD) technique. The study of Li-C intercalation processes of the graphitized coke reveals that there are three major types of intercalation behavior. The first is uniformly intercalated at all Li-C compounds in graphitized coke heated at 2250 degreesC; the second is obviously staging phenomenon during intercalating for the graphitized coke heated at 2750 degreesC; the third is cointercalation of solvated Li-ion at high potential (>0.3V) and then lithium electrochemical intercalation at lower potential for that heated at 3000 degreesC, resulting in the decrease of capacity and efficiency of graphite negative electrode for lithium-ion secondary battery.