Enhancing F-CapMix Performance—Novel Multilayer Graphene-Protected Metal Current Collectors

Salinity gradient power harvesting through flow-electrode capacitive mixing (F-CapMix) represents an emerging technology in renewable energy. This innovative approach enables continuous electrical power generation via circulating flow-electrodes, eliminating intermittent processes. Traditionally, graphite has been the preferred current collector in F-CapMix systems due to its high electrical conductivity and resistance to seawater corrosion. However, the use of insulating polyacrylate-based polymers for graphite shaping compromises electrical conductivity, impeding efficient charge percolation in flow-electrodes. While metal current collectors offer superior conductivity, their susceptibility to seawater corrosion limits their application. Our research introduces a groundbreaking solution: multilayered graphene as a protective coating for metal current collectors in F-CapMix systems. We synthesize this graphene layer on metal substrates using chemical vapor deposition, combining high electrical conductivity with excellent corrosion resistance. We conducted comprehensive chemical and electrochemical analyses of these graphene-coated current collectors, optimizing graphene growth parameters on metal substrates. Our findings demonstrate that the multilayered graphene effectively shields against seawater corrosion while facilitating efficient charge percolation. Implementing multilayered graphene-coated Ni current collectors in F-CapMix cells yielded remarkable results. We achieved a power density of 0.75 W/m² and a current density of 22.3 A/m², nearly doubling the performance of conventional graphite collectors. This innovation significantly enhances F-CapMix technology, paving the way for more efficient salinity gradient power harvesting and broadening its potential applications in renewable energy systems.