Offshore self-powered communication and positioning enabled by efficient conversion of renewable salinity energy into green power utilizing low-cost asymmetric nano-hybrid hydrogel membrane

Efficient conversion of salinity energy into green power is an innovative renewable energy technology towards offshore electricity supply and utilization. Improving the conversion efficiency through sustainable strategies, low-cost materials, and facile processes still remains a challenge. In this work, a strategy of constructing a three-dimensional nano-hybrid hydrogel membrane with gradient charge density is proposed. The charged nanoparticles fabricated by post modification of commercial ZnO is dispersed in the hydrogel to ensure high selectivity for ion transport. The asymmetric pore structure in the hydrogel membrane provides high transport capacity for ion transport. The cost of nano-hybrid hydrogel membrane is as low as 0.0122 $ g−1. After optimizing the effect of different environmental conditions on the membrane performance, a power density of 4.33 W·m−2 and an energy conversion efficiency of 33.6 % are obtained. To overcome the volatility of the power production, a capacitor is utilized to collect and store the electrical energy converted from salinity energy. The charged capacitor is coupled with offshore self-powered electronics and successfully communication and positioning. This work proposes offshore application scenarios for efficient conversion of renewable salinity energy into green power through sustainable technology.