High value tantalum capacitors using organic semiconducting cathodes - uses tantalum foil with powdered tantalum sintered to its surface

摘要

The Ta-capacitors with semiconducting cathode feature a Ta-foil or sheet which has on one or both surfaces Ta powder attached by sintering and an organic semiconducting cathode. The Ta-powder layer is pref. 0.01-0.5mm thick, esp. 50-100 micron. The carrier is pref. etched Ta-foil or sheet. The organic semiconductors used as cathode are pref. a TCNQ-complex, polyethylene, polypyrrole, polyaniline or polythiophene. The foil or sheet can be folded or spiralled and the cathode material is applied after the final shape has been achieved. Contacts can be made by including an Al-foil in the windings. USE/ADVANTAGE - The use of the modified foil or sheet results in a large are Ta-electrode which has a reduced penetration depth compared with a current sintered powder electrode. This allows easier penetration by the cathode material. The resulting electrode area is much larger than can be achieved using etched foils.