Planar integration of flexible micro-supercapacitors with ultrafast charge and discharge based on interdigital nanoporous gold electrodes on a chip

Flexible, wearable, implantable and easily reconfigurable micro-fabricated pseudocapacitors with impressive volumetric stack capacitance and energy densities are desired for electronic devices. In this work, scratching technology at the micron-scale enables construction of the planar electrode systems directly based on nanoporous gold films. We demonstrate that both nanoporous channels with high ion-accessible ability and interconnected skeletons with high conductivity enable the design of pseudocapacitive micro-supercapacitors with high performances. These planar devices show several attractive features including ultrafast charge/discharge (high rate), large capacitance (1.27 mF cm−2, 127 F cm−3), and ultrahigh energy density (0.045 W h cm−3) while maintaining a high power density (22.21 W cm−3). Especially, the superb cyclability and mechanical flexibility give them great potential for future microelectronics with a tiny volume. The design concept reported here provides an avenue to integrate planar micro-supercapacitors into large-scale devices with a small environmental footprint.