Hydrovoltaic Cell Using Non-Woven Fabric

As the problems of global warming and the energy crisis become more and more apparent, the development and utilization of environmentally friendly, sustainable, and renewable resources is essential for humanity. Water is the most abundant, sustainable, and clean resource on Earth, capturing about 70% of the solar energy received by the Earth's surface. Therefore, extracting electrical energy from water as one of the renewable strategies has attracted recent research interest.<br/>Hydrovoltaic cells have the major advantages of being cheap to produce because they do not use vacuum equipment, eco-friendly because they do not use materials that cause environmental pollution, and cheap to produce because they use carbon nanoparticles such as carbon black, which have recently become cheaper. Power generation using hydrovoltaic cells utilizes the property that an electrical double layer (EDL) forms at the interface of a charged solid surface when it comes in contact with water, and when a pressure gradient induces fluid flow through the space, a streaming current is generated. To date, several materials are being investigated for the development of hydrovoltaic cells, including graphene oxide, carbon black, carbon nanotubes, solid oxides, layered double hydroxide materials, and natural wood. These materials are functional, eco-friendly, and the manufacturing process is (mostly) vacuum-free and environmentally friendly. The cost of production is also very low, making it very competitive with other renewable energies. Hydrovoltaic cells show great potential in the fields of basic power generation equipment, solar energy evaporators, and self-generation equipment due to their advantages of non-pollution, low cost, and high portability. However, the disadvantage is that the device performance is still low.<br/>In this study, hydrovoltaic cells were fabricated by adsorbing carbon nanoparticles such as carbon black dispersed in water on nonwoven fabrics such as cellulose acetate and rayon. A small amount of surfactant was used in the process of dispersing carbon nanoparticles. The dry hydrovoltaic cell was then electrode-formed using a stretchable conductor to measure its properties. The devices were fabricated by varying the amount of carbon nanoparticles and the physical dimensions of the device, and the properties were measured by varying the humidity and temperature. Through this study, we identified various factors for improving hydrovoltaic cell performance and confirmed the possibility of manufacturing high-performance cells.