SBIR Phase I: Advanced Carbon Electrodes to Reduce Ultracapacitor Size and Cost

This Small Business Innovation Research (SBIR) Phase I Project will significantly increase the energy density and reduce the manufacturing cost of ultracapacitors for NGV applications. Cell voltage constraints presently limit the energy density and increase the number of cells required for high voltage ultracapacitors. The composition of porous carbon electrode materials will be modified to adjust the open circuit potential, thereby increasing the cell voltage. Anodically stable electrolytes will be investigated to further increase cell voltage. The objective is to increase cell voltage to 3.6 V versus 2.5 V typical for present commercial carbon-based ultracapacitors. Since energy density scales with 2 V, 3.6 V cells would more than double the energy density. This increase would also reduce manufacturing cost by reducing the number of cells in high voltage devices by >30%. Prototype capacitor cells will be prepared and evaluated to determine the cell voltage window. Extended charge/discharge and constant potential measurements will be made to assure that the increased cell voltage is sustained. Ultracapacitors complement or replace batteries in applications where weight, peak power, and battery life are key factors. Commercial applications include cellular phones, power conditioning (UPS), electromechanical actuators, and conventional or next generation vehicles.