Patent ID: 7572553

Claim:
A high-density electrode, obtained by impregnating a high-density electrode which comprises an electrode active substance and carbon fiber having a fiber filament diameter of 1 to 1,000 nm and has a porosity of 25% or less, with a solid polymer electrolyte, wherein the electrode active substance is a carbon material, wherein the carbon material contains a graphite material in an amount of 50 mass % or more, and the bulk density of the electrode is 1.7 g/cm 3 or more, and wherein the graphite material is carbon particles containing, in an amount of 50 mass % or more, graphite particles satisfying the following requirements: (1) C 0 of a (002) plane as measured by means of X-ray diffractometry is 0.6900 nm, La (the size of a crystallite as measured along the a-axis) is greater than 100 nm, and Lc (the size of a crystallite as measured along the c-axis) is greater than 100 nm; (2) BET specific surface area is 0.2 to 5 m 2 /g; (3) true density is 2.20 g/cm 3 or more; and (4) laser Raman R value (the ratio of the intensity of a peak at 1,360 cm −1 in a laser Raman spectrum to that of a peak at 1,580 cm −1 in the spectrum) is 0.01 to 0.9.