Abstract
For electrochemical reduction of graphite intercalation compounds with sulfuric acid (H2SO4-GICs) synthesized by chemical oxidation in sulfuric acid solution with an excess amount of oxidant, a large amount of electrical quantity was needed much larger than that for the reduction of the compound synthesized by electrochemical oxidation. This experimental result seemed to be explained by the competition between the chemical oxidation to H2SO4-GICs in sulfuric acid solution with the chemical oxidant and the electrochemical reduction of H2SO4-GICs. In the case of nitric acid oxidation, even though H2SO4-GICs was electrochemically reduced to graphite, the graphite was chemically oxidized by opening the circuit and again sulfuric acid was intercalated into the gallery of graphite, accompanying the increase in potential. More than 20 cycles of electrochemical discharging and chemical charging were performed with 4mA discharge current.
Based on this reaction cycle, chemical oxidation to and electrochemical reduction of H2SO4-GICS was constructed a battery by using graphite and lead metal as positive and negative electrodes, respectively. Its discharging showed well-defined plateau and larger capacity than theoretical one was obtained.
