In conclusion, a series of WIEGs based on CBNP-coating and different current collectors are designed to investigate the role of electrochemistry in the electricity generation process. Significantly, it is found that the electricity generation is mainly originate from the electrochemical (redox) reactions at the liquid-solid interfaces involved with water, CBNP, current collectors, and dissolved oxygen. Besides, it is identified that introducing functional groups such as -COOH and -OH on the surface of the CBNP improves the output performance of the WIEG. It is also proved that adding salt or acid in water can promote the electrochemical reaction at the water-metal current collector interface and inhibit the undesirable negative voltage induced by the dissociation of surface functional groups. Based on these findings, a semi-solid-state sandwich-type AWIEG is fabricated with an average output voltage and current density of 1.25 V and 17.1 μA cm -2 , respectively. It can power a commercial temperature and humidity sensor continuously for 5 days and serve as a power source for modulating OECT, demonstrating its potential as a low-cost power supply for portable/wearable electronics. Overall, the verified electrochemical and physical reactions at the liquid-solid interfaces provide new insights for deeper understanding of the mechanisms of waterinduced electricity generation, which are critical for guiding new developments in this emerging technology.