All-Wood-Based Ionic Power Generation Triggered by Wastewater for Environmental Management

Abstract

Abstract Water evaporation-aided electricity harvesting has gained much on significance for energy sustainability. All-bio-based hydrovoltaic materials increase the attractiveness of this strategy. Although promising, it faces a challenge due to its reliance on freshwater and its inherently low power output. Herein, we demonstrate the feasibility of reuse of alkaline wastewater for the first time to develop an all-wood-based water-induced electric generator (WEG) based on ion concentration gradients. The combination of evaporation-driven liquid flow and uneven distribution of electrolyte endows delignified wood with the difference of ion concentration along aligned cellulose nanochannels, thus supplying electrical power. The practice of using alkali reservoirs including industrial wastewater further contributes to electricity generation. The cubic WEG with a side length of 2 cm can produce an ultra-high open-circuit voltage of about 1.1 V, and a short-circuit current of up to 320 μA. A remarkable power output of 6.75 μW cm–2 is correspondingly realized. Series-connected WEGs can be used as an energy source for commercial electronics and self-powered systems. Our design provides a double value proposition, allowing at the same time for sustainable energy generation and wastewater reuse.