Multifunctional devices based on planar microsupercapacitors: Progress and challenges

With the boom of portable, wearable, and implantable smart electronics in the last decade, the demand for multifunctional microscale electrochemical energy storage devices has increased. Owing to their excellent rate performance, high power density, long cycling lifetime, easy fabrication, and integration, multifunctional planar microsupercapacitors (PMSCs) are deemed as one of the ideal micropower sources for next-generation flexible on-chip electronics. Therefore, we offer a comprehensive overview of the recent progress regarding multifunctional devices based on PMSCs, including stretchable, self-healing, stimulus-responsive, thermosensitive, biodegradable, and temperature-tolerant microdevices. We also emphasize the unique applications of multifunctionally integrated PMSCs in the construction of self-powered and sensor-integrated systems in terms of multifunctional operation modes. Finally, the key challenges and future prospects related to these multifunctional devices are discussed to stimulate further research in this flourishing field.