Abstract
Salinity gradient energy is a sustainable, clean, and renewable ocean energy source. In this work, we used citric acid, phosphoric acid, and nitric acid to modify the surface of activated carbon. Based on the electrochemical capacitive mixing technology, a salinity gradient energy extraction device was constructed using acid-modified activated carbon as cathode and MoS2/MWCNTs as anode. Surface modification by different acids improves the performance of activated carbon electrodes for salt gradient energy conversion in the salt difference battery. The modification effect of nitric acid was the most pronounced, the specific capacitance of the modified electrode reaches 156 F g−1, and the concentration response voltage reaches 170 mV, with the assembled energy extraction system obtaining an energy density of 10.65 J m−2, an enhancement of 53.0% compared to the unmodified activated carbon electrode.