Reactions for Self-Powered

elf-powered systems have been devel-oped to integrate variable devices into a standalone system with multiple functions, including sensing, communi-cation, computation, etc.1,2 The wireless, miniaturized, and large number of compo-nents in the system require a renewable, sustainable, and clean power supply, and energy harvesting from the ambient envi-ronment will be a perfect solution for this problem.38 In this regard, the triboelectric nanogenerator (TENG) was recently in-vented to convert mechanical energy into electricity, based on the coupling effect of contact electrification and electrostatic induction.9,10 In the past few years, the out-put performance of the TENG has been improved drastically through advanced structural design and material optimiza-tion.1115 By using nanogenerators as the power source, various types of self-powered systems were successfully demonstrated, such as wireless sensor networks,16,17 elec-trochemical reactions,18,19 chemical sen-sors,20 home appliances,15,21 and security detection.22 To realize practical and com-mercial applications of the self-powered system, a fully integrated device with inde-pendent working capability is highly de-sired. Recently, transparent and flexible TENGs have provided a new route to harvest ambient mechanical energy and are more suitable for integration in wearable elec-tronic devices.2325 Electrochromic devices (ECDs) are devel-oped to provide reversible changes of their * Address correspondence t