Ionomer Composite Thin Film Capacitors

Ionic polymer metal composites (IPMCs) are one of the newest and most promising materials being studied for their electromechanical properties. They are robust and light-weight, and can be fabricated easily into nearly any desired size or shape. It is already well known that IPMCs, if prepared properly, can produce large macro-bending deformations while under low driving voltages or, conversely, produce measurable electric signals (sensing) when deformed. The recent discovery of capacitative behavior in dry-prepared IPMCs has led to the development of high energy density devices. Here we report on a single-step microfabrication of metal electrodes to produce ionomer composites sandwiched between two thin metal films. These composites exhibit a capacitance per unit planar area of ~1.0 mF cm^-2, or 40 mF/g, for a 127 μm-thick ionic polymer substrate with 100-nm thick Au (5 nm-thick Cr for adhesion) electrodes. We further report on the scalability of these devices. These composites could open the door to high energy density, flexible, and scalable thin films needed to meet the energy storage solutions of the future.