Ag/Reduced Graphene Oxide/Carbon Fiber Composites as Electrodes for Highly Stable and Responsive Marine Electric Field Sensors

The increasing demand for maintenance-free, cost-effective,andhigh-stability flexible electrodes is highly anticipated for the researchof marine electric-field sensors, and various carbon fibers (CFs)are considered the most suitable carbon-based electrode for the purpose.Nevertheless, the conventional fabrication of acidified or nitrogenizedCF electrodes did not attract great attention for commercial application,which has limitations in the case of simultaneous cost-effectivenessand long-term stability. In this study, with homemade reduced grapheneoxide (rGO) load, the prepared double carbon substrate Ag-rGO-CF compositeelectrodes have a honeycomb rGO conductive skeleton and the dispersedAg nanoparticles via a facile hermetic oxidation process and hydrothermalmethod. The prepared Ag-rGO-CF composite electrode demonstrated anoutstanding electrode performance, including low resistance, highelectrochemical reaction rate, and stable potential with long-termstability and low cost. The electric double-layer (EDL) structuretheory from the Gouy-Chapman-Stern model and doublecarbon substrate mechanism between CFs and rGO with the help of Agwere clarified, whose principle is to strengthen the adsorption forceand electrostatic attraction of the electrode and to offset the residualcharge while reducing the thickness of the electric double layer toachieve the purpose of potential balance. The Ag-rGO-CF compositeelectrode has presented long-term stability and high sensitivity,especially a wide application bandwidth. The Ag-rGO-CF composite electrodemade in this study is a competitive candidate material as a flexiblemarine electrode field sensor.