The electrochemical behavior of natural graphite in sulfuric acid electrolyte with concentrations ranging from 10 to 18 M and thermodynamic properties of the synthesized sulfate graphite intercalation compounds (H2SO4-GICs) were investigated at a temperature range of 0-80 degrees C using chronopotentiometry and cyclic voltametry. The results show that the onset potential required to synthesize GICs and the stage transition potentials all decrease with electrolyte concentration, but increase with temperature.