The role of electrochemistry and surface chemistry in water-induced electricity generation from electrically conductive solids

Water-induced electricity generators (WIEGs) based on solid-water interactions are considered as promising next-generation power sources due to the abundance and sustainability of water. Nevertheless, the contributions of electrochemistry and solid surface chemistry to the electricity generation of WIEGs have not gained enough attention. Here, a series of WIEGs is designed to investigate the effects of different pairings of electrically conductive solids, device configurations, solid surface chemistry, and electrolytes in water on the electricity generation. It is revealed that the electricity generated from these devices is mainly ascribed to the electrochemical reactions involved by the conductive solids, dissolved oxygen, and liquid water that convert chemical energy into electricity. The dissociation of surface functional groups also affects the generated voltage in different electrolytes. The output performance can be enhanced by using more active solids and salty/acidic electrolytes. Finally, a semi-solid-state portable WIEG capable of producing stable voltage for at least 30 days was constructed, demonstrating great potential for driving portable/wearable/flexible electronics and internet of things devices.