Tailoring of a Piezo‐Photo‐Thermal Solar Evaporator for Simultaneous Steam and Power Generation

Abstract

AbstractWater and electricity shortages constitute a global energy crisis that cannot be ignored. The sun is an unlimited source of energy, and oceans provide abundant water and renewable energy resources. In this study, poly(vinylidene fluoride) (PVDF)/graphene solar evaporator membranes are fabricated for simultaneous freshwater production and power generation. Graphene addition transformed the PVDF crystal from the α‐phase to the piezoelectric self‐assembly β‐phase. The resulting membrane is used to convert the mechanical energy of waves to electrical energy. The membrane has an output voltage of 2.6 V (±1.3 V) and an energy density of 2.11 Wm−2 for 1 Hz simulated waves, which are higher than values reported in the literature. The stacked graphene and polymer formed a wood‐lumens‐like mesoporous structure with a photothermal effect. Under one sun illumination, the water production rate is 1.2 kg m−2 h−1, and the solar‐thermal energy conversion efficiency is 84%. Finally, a prototype is built to prove a single evaporator's feasibility that can simultaneously obtain freshwater and generate electricity. Thus, this membrane serves as an ocean wave power generation device that can provide all‐weather energy generation, convert stored electrical energy into thermal energy at night and on cloudy days, and continuously provide safe drinking water.