Self-supported printed multi-layer capacitors

Abstract

The increasing demand for miniaturized electronic devices has elevated the need for rechargeable micro-power sources. While lithium and lithium ion batteries have been utilized in these applications since the late 1990s, other energy harvesting technologies, such as mechanical, thermal and solar, are now being used to augment batteries to enable systems to be self-powered.However, the lifetime of any battery is finite, which may be a major problem when the application is in a permanent structure or medical implant device. For power or significant energy storage applications, printed multilayer capacitors or supercapacitors are being explored as an enhancement, or replacement of micro-batteries.

The printing of multilayer capacitors offers an inexpensive manufacturing process for these devices. Though the ability to print supercapacitor electrodes, supercapacitors, and batteries on rigid and flexible substrates is well known, having a device supported by a substrate is not always advantageous. This is especially true for cases where the rigidity of the substrate limits the extent to which the device can be bent or wound, or where substrate compatibility issues to the surface to which it is to be attached is faced. The ability to bend or wind devices can improve the attachment to surfaces; enable its placement in confined spaces and advance efforts to further miniaturize devices.In this research, a sacrificial water-soluble polymer layer was used to produce self-supported (substrate free) printed conductive and dielectric ink fims of different thicknesses, as well as a completed capacitor. The electrical and mechanical properties of these films and the capacitor were measured. Such measurements have not yet been reported and should therefore advance our understanding of properties at different thicknesses.