Preparation and Characterization of a High-Stability, Low-Noise Ag/AgCl Sensor for Marine Electric Field Measurements

A new Ag/AgCl sensor for measuring marine electric fields was prepared and characterized through electrochemical methods and scanning electron microscopy. Its performance was evaluated in both laboratory and deep-water settings. The study indicates that the double-pulse electrodeposition method is advantageous for producing Ag/AgCl sensors that maintain excellent stability over time. During a 20-day continuous stability test, the potential difference of the sensor consistently remained between −24.76 μV and 62.07 μV, with a minimum potential difference drift of 2.77 μV per 24 h. All sensors accurately detected artificial signals in both the time and frequency domains, and their responses were consistent with one another. The minimum noise level of the sensor was 0.59 nV (\sqrt \rm Hz )⁻¹@1 Hz. The sensor performed well in high-precision electric field measurements at a depth of approximately 2800 m in the South China Sea. The high stability and low noise level of the sensor make it an effective tool for detecting electrical conductivity structures beneath the seafloor.