Technical Papers
Properties and Performance of Hybrid Aluminum Electrolytic/Electrochemical
Capacitors
presented at the 16th Capacitor and Resistor Technology Symposium (CARTS),
March 11-15, 1996
John R. Miller and David A. Evans
Summary
Test data was recently presented for a hybrid electrolytic/electrochemical capacitor having sintered tantalum anodes and RuO2 cathodes. A 50-V, 18-mF capacitor of this design has electrical performance that was comparable to an advanced aluminum electrolytic capacitor but with only one-tenth the volume and one-half the mass. This design, however, is expensive because of the tantalum anode. RuO2 cathode costs are negligible.
Here, for the first time, we report test results for aluminum hybrid capacitors. These were fabricated with etched aluminum anodes, RuO2 cathodes, and electrolytes that are compatible with aluminum and its oxide. Anodes rated at 6.3 to 250 V were used. Although cathode pseudocapacitance was diminished using the aluminum-compatible electrolytes, test data confirms that the aluminum hybrid concept is viable. Impedence data of these test devices is almost identical to those of controls fabricated with the same anodes but with aluminum cathodes. Hybrids having a more optimum aluminum anode structure should maintain the attractive performance, weight, and size advantages of the hybrid approach at a more affordable cost than tantalum.