Technical Papers

The Littlest Big Capacitor -- An Evans Hybrid
presented at the Fifth International Seminar on Double Layer Capacitors and Similar Energy Storage Devices, December 4-6, 1995
David A. Evans

High-energy density capacitors with a tantalum metal anode, Ta2O5 dielectric, aqueous electrolyte, and RuO2 cathode have been described. Known as Evans Hybrid capacitors, these devices have the high energy density of electrochemical capacitors with the improved a.c. behavior of electrolytic capacitors. Single-cell working voltages up to 215 volts have been demonstrated. Capacitors of this type, with multiple elements arranged in parallel within a single case, and improved packaging techniques have now been assembled. Perfoemance data on a 50 V, 18 mF hybrid capacitor are presented.