Printed supercapacitors: Materials, printing and applications

Supercapacitors hold great promise for future electronic systems that are moving towards being flexible, portable, and highly integrated, due to their superior power density, stability and cycle lives. Printed electronics represents a paradigm shift in the manufacturing of supercapacitors in that it provides a whole range of simple, low-cost, time-saving, versatile and environmentally-friendly manufacturing technologies for supercapacitors with new and desirable structures (micro-, asymmetric, flexible, etc.), thus unleashing the full potential of supercapacitors for future electronics. In this review, we start by introducing the structural features of printed supercapacitors, followed by a summary of materials related to printed supercapacitors, including electrodes, electrolytes, current collectors and substrates; then the approaches to improve the performance of printed supercapacitors by tuning printing processes are discussed; next a summary of the recent developments of printed supercapacitors is given in terms of specific printing methods utilized; finally, challenges and future research opportunities of this exciting research direction are presented.