ALL-SOLID-STATE ELECTRIC DOUBLE-LAYER CAPACITOR USING POLYMER ELECTROLYTE AND ISOTROPIC HIGH-DENSITY GRAPHITE-ELECTRODES

Isotropic high density graphite (HDG) was used as the polarizable elec trode of electric double layer capacitors (EDLC) with a solid electrol yte consisting of PEO/LiClO4([EO]/L[i(+)]=8:1) at 80 degrees C or with a gel electrolyte consisting of PEO/PC/LICLO(4) ([EO]/[PC]/[Li+]=8:8: 1) at room temperature. The all-solid state capacitor with HDG electro des works satisfactorily as a EDLC with a relatively high capacitance, as well as the EDLC with gel electrolyte PEO/PC/LiC1O(4). These EDLCs with solid polymer electrolyte PEO/LiClO4 and gel electrolyte PEO/PC/ LiClO4 show good charge/discharge behavior when charged to 1.5 V at 80 degrees C and 20 degrees C, respectively.