title: Influence of electrolytes (TEABF4 and TEMABF4) on electrochemical performance of graphite oxide derived from needle coke.
abstract: The structure of needle coke was changed to graphite oxide structure after oxidation treatment with 70 wt.% of nitric acid and sodium chlorate (NaClO3), and the inter-layer distance of the oxidized needle coke was expanded to 6.9 angstroms. The first charge profile of the oxidized needle coke-cell with 1.2 M TEMABF4/acetonitrile solution displayed that the intercalation of electrolyte ions into the inter-layer occurred at 1.0 V, which value is lower than 1.3 V of the oxidized needle coke-cell with 1.2 M TEABF4/acetonitrile solution. After first charge/discharge, the cell using TEMABF4 electrolyte exhibited smaller electrode resistance of 0.05 omega, and larger specific volume capacitance of 25.5 F/ml at the two-electrode system in the potential range 0-2.5 V than those of the cell using TEABF4 electrolyte. Compared to the TEABF4 electrolyte, better electrochemical performance of the TEMABF4 electrolyte in the oxidized needle coke may be caused by the smaller cation (TEMA+) size and better ion mobility in the nanopores between inter-layers.
authors.affiliation: Battery Research Center, Electrotechnology Research Institute, Changwon 641-120, Korea.
authors.forename: Sunhye
authors.initials: S
authors.lastname: Yang
authors.forename: Ick-Jun
authors.initials: IJ
authors.lastname: Kim
authors.forename: In-Sik
authors.initials: IS
authors.lastname: Choi
authors.forename: Mi-Kyeong
authors.initials: MK
authors.lastname: Bae
authors.forename: Hyun-Soo
authors.initials: HS
authors.lastname: Kim
mesh_terms: D003077:Coke; D004553:Electric Conductivity; D004573:Electrolytes / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010087:Oxides / Q000737:chemistry; D010316:Particle Size; D013499:Surface Properties
chemical_list: D003077:Coke; D004573:Electrolytes; D046911:Macromolecular Substances; D010087:Oxides; D006108:Graphite