Performance Evaluation of Seawater Battery Power Generation in a Monitored Environment

Continuous or long-term monitoring of the deep-sea is essential for evaluating its natural resource potential, economic value (such as oil and mineral resources), and biodiversity. However, it encounters significant energy challenges because traditional energy sources-such as waves, tides, sunlight, and wind-are not feasible at the ocean bottom. Seawater batteries (SWB) have emerged as a promising alternative, offering high theoretical energy density, safety, economy, and environmental benefits. SWBs generate energy through the oxidation of a reactive metal anode, like a magnesium alloy, and reduction reactions at the cathode, using seawater as the electrolyte. Research highlights magnesium SWBs' potential, demonstrating their ability to provide stable power over long periods. This study investigates the efficiency of reduced-cost magnesium alloy batteries with carbon materials, assessing various configurations and their performance concerning water parameters. The experiments revealed that magnesium alloy paired with a graphite-nickel foam cathode performed better than the carbon fiber brush with titanium wire. Testing the Mg-Graphite-Nickel foam battery prototype in a controlled environment showed a specific energy output of 552.96 Wh/kg and a power output of 42 mW for a magnesium mass of 260 g. Analysis of water parameters such as temperature, dissolved oxygen, pH, redox potential, electrical conductivity, and salinity indicated their significant impact on battery performance. The findings suggest that SWBs can meet the energy needs of underwater sensors, providing a viable and eco-friendly solution. Further research and development could optimize these batteries, enhancing the longevity and efficiency of seafloor monitoring systems.