Advanced Hydrovoltaic Energy Generation using a Hierarchical NiFe LDH-Decorated CuO Nanowire Mesh Device

The contemporary energy landscape is undergoing a transformative shift, driven by the dual imperatives of environmental sustainability and technological advancement. As traditional energy sources deplete and global concerns over carbon emissions and environmental degradation mount, there's a pronounced urgency to find viable renewable energy solutions. Central to this quest is the principle of energy harvesting—capturing ambient energy from the environment and converting it into usable electrical power. Traditional methods such as solar and wind, while revolutionary, come with their own sets of challenges including intermittency and geographical limitations. In such a scenario, the prospect of harvesting energy from more omnipresent and less variable sources has gained significant scientific attention. Hydrovoltaic energy, which leverages the potential energy in water, presents one such avenue. The structural foundation of this advanced hydrovoltaic device is a meticulous assembly of nickel-iron layered double hydroxides (NiFe LDHs) deposited on copper oxide nanowires (CuO NWs). These NWs are firmly anchored to Cu meshes, creating a stable yet intricately detailed hierarchical nanostructure. Such a configuration has been optimized for the rapid diffusion of ion-rich water infiltration. Central to this capability is the LDH layer, which acts as a mediator, enhancing the device's inherent hydrophilic attributes and subsequent energy-harvesting efficiency. When subjected to a 3.3 M CaCl₂ solution droplet of 200 µL, the device consistently registers a power output in the vicinity of 250 nW/cm³. Remarkably, the energy generation capability of this configuration remains robust over prolonged durations, with a life cycle exceeding one month without noticeable degradation. The underlying mechanisms propelling this efficiency were thoroughly investigated. We identified that the NiFe LDH layer plays a pivotal role in augmenting the potential difference across the device, resulting in enhanced electricity generation. The electricity stemming from ionic infiltration and diffusion was elucidated, and strategies for device renewability were explored. Anticipating industrial applications, we also evaluated the device's scalability. Emphasis was placed on serial allocation strategies, demonstrating the potential for modular expansion and integration into larger systems. Collectively, this research signifies a substantial stride in hydrovoltaic energy generation, utilizing sophisticated nanostructures to effectively capitalize on readily available hygroscopic salts and seawater, paving the way for future green energy applications.