Electrochemical properties of nitrogen-substituted carbon and organofluorine compounds

The CxN samples(C14N-C62N) prepared with a nickel catalyst had the higher crystallinity and less pyridine-type nitrogens existing at the edge of graphene layers than CxN prepared in the absence of a catalyst. With increase in the deposition temperature of CxN, the cycleability for electrochemical intercalation-deintercalation of lithium ions was improved and the profile of the charge-discharge curve approached that of graphite due to increase in the crystallinity and decrease in the incorporated nitrogens. CxN-coated graphites demonstrated gradual increase in the potential at the last stage of lithium ion deintercalation process. The effect of fluoroester-mixing in 1 M LiClO4-EC/DEC was also investigated at a low temperature. It was found that CHF2COOCH3 with a low molecular weight and a small number of fluorine atoms was effective as a mixing agent.