Multifunctional and Physically Transient Supercapacitors, Triboelectric Nanogenerators, and Capacitive Sensors

Electronic waste (e-waste) grows in parallel with the increasing need for consumer electronics. This, unfortunately, is leading to pollution and massive ecological problems worldwide. A solution to this problem is the use of transient electronics. While transiency of a few components such as transistors and batteries have been proposed already, it is crucial to have all components in electronic devices to be transient. Therefore, the transiency of more electronic components should be demonstrated to alleviate the e-waste problem. Herein, multifunctional nanocomposite electrodes are fabricated using poly(vinyl alcohol), carbon black, and activated carbon. These simple electrodes are then used to fabricate physically transient supercapacitors, triboelectric nanogenerators, and capacitive sensors. Transient supercapacitors are used numerous times with excellent supercapacitive behavior before being discarded, which show promise as an energy storage component for transient systems. The fabricated transient triboelectric nanogenerators are used to harvest mechanical energy, eliminated the need for an external power supply, paving the way to self-powered devices, such as a touchpad as demonstrated herein. The fabricated transient capacitive sensors, on the other hand, have shown long linear sensitivities and offered waste-free monitoring of physiological signals and body motions.