Recent Progress in Transient Energy Storage using Biodegradable Materials

With the development of wireless sensor networks, electrical waste that remains in the environment is an inevitable issue in achieving sustainability and progress in electronics. Transient electronics that disappear after a prescribed time are of interest in electronics and material sciences. Such devices comprise naturally sourced materials that degrade without harmful or toxic substances during biodegradation. Although there are reports on transient electronic devices, including transistors, sensors, and radio frequency circuits, insufficient research has been conducted on the energy storage essential for operating transient devices. This review highlights the recent progress in developing transient energy storage. First, materials for transient energy storage, including conductors, electrolytes, and gels, are introduced. Second, transient supercapacitors, pseudocapacitors, primary batteries, and secondary batteries, are described and summarized. Finally, this review concludes and discusses the prospect of transient energy storage. The continuous progress of transient batteries and integration with transient devices are promising for sustainable electronics in the future.