Everyday Materials for Transient Supercapacitors

Due to the substantial advancements achieved in wearable technology, including consumer electronics and medical monitoring devices, there has been a sharp rise in electronic waste during the past ten years. As electronic devices contain hazardous materials and have limited recyclability, the environmental threat is steadily increasing and the volume of e-waste grows exponentially each year. A significant portion of electronic waste comprises energy storage devices that consist of materials that are toxic or non-recyclable. Therefore, research and development in green energy storage systems that are made of non-hazardous materials is highly needed. Transient electronics, which are intended to disintegrate at the end of their use or when required, have emerged as a solution to this need, producing nearly little waste.<br/><br/>Green and transient electronics require transient energy storage units. Being biodegradable, biocompatible, and non-toxic are essential properties that energy units must possess in line with the requirements of transient electronics. This is especially important for on-demand electronics, which are mostly used for health monitoring devices such as ingestible or implantable devices.<br/><br/>Herein, we propose transient and even edible supercapacitors with everyday materials – such as supplements and foods [1,2]. We successfully fabricated transient supercapacitors based on all-PVA layers and successfully achieved a perfectly working EDLC type supercapacitors with an excellent rate capability up to 1 V.s^-1. The entire structure is based on biodegradable and biocompatible products and showed excellent physical transiency in simple aqueous solutions. To further this quest, we also successfully fabricated cellulose-based edible supercapacitors utilizing soy-sauce based, zwitterionic gel as an electrolyte. Fabricated food-based gel has shown to enhance the L929 proliferation – which is an excellent indication of biocompatibility – and allowed a textbook-like capacitive behavior due to its excellent ionic conductivity. Simulated gastric fluid tests shown a complete dissolving of the edible supercapacitors, indicating its digestibility. These studies indicate excellent developments in the production of transient and edible supercapacitors, being fresh prospects to be the energy units for environmentally friendly and biocompatible transient electronics.<br/><br/>[1] M. B. Durukan, M. O. Cicek, D. Doganay, M. C. Gorur, S. Cinar, H. E. Unalan, Multifunctional and Physically Transient Supercapacitors, Triboelectric Nanogenerators and Capacitive Sensors, Advanced Functional Materials 32 (2021) 2106066.<br/>[2] M. B. Durukan, D. Keskin, Y. Tufan, O. Dincer, M. O. Cicek, B. Yildiz, S. Cinar Aygun, B. Ercan, H. E. Unalan, An Edible Supercapacitor Based on Zwitterionic Soy Sauce-Based Gel Electrolyte, under evaluation.