All Wood‐Based Water Evaporation‐Induced Electricity Generator

Abstract Water evaporation‐induced electricity generators (WEIGs) are promising as self‐powered electronic devices, as they can harvest green, small‐grade, and ubiquitous hydrovoltaic energy in ambient environment to electricity. Here, biodegradable wood‐based WEIGs with high performance are reported by removing lignin and hemicellulose from balsa wood (BW) with more exposed cellulose nanofibrils. Delignified BW (DBW) and cellulosic BW (CBW) display significant enhance in open circuit potential ( V oc ) and short circuit current ( I sc ) due to increased specific surface area, hydrophilicity, and surface charge density. The electricity‐generating performance of CBW‐based WEIG (CBWG) is not stable due to its structural collapse. DBW‐based WEIG (DBWG) shows a steady electricity output and fast responsivity to ambient environments, such as humidity, temperature, light, and wind. Therefore, DBWGs can be employed as self‐powered environmental sensors. The effects of different kinds of electrolytes with varied concentrations on the performance of DBWG are also studied. The DBWG (40 mm × 40 mm × 2 mm) displays a V oc of 0.77 V and I sc of 148 µA in 1.2 m CaCl 2 solution. In this study, all wood‐based sustainable WEIGs with high electricity generating performance are facilely prepared and are promising for remote self‐powered environmental sensors and power sources.