Study on preparation of electrically grafted dicyandiamide modified carbon fibre electrode for marine electric field and its electric field response performance

Abstract

Surface amino modification of carbon fibre electrodes can significantly improve their electrochemical and electric field response properties. In this paper, we tune up the grafting voltage (3, 5, 7 V) and graft polyaminocyanine films on the surface of carbon fibres to modulate the structure and electrochemical properties of the electric double layer at the electrode/sea water interface. The results show that the higher the grafting potential, the more uniform the polyaminocyanine film on the carbon fibre surface and the more stable the electrode bilayer structure. The CF-7V has the best overall performance with a specific capacitance of 9.368 F·g-1, 31.6 times that of the blank group; the charge transfer resistance and low frequency capacitive resistance are significantly reduced; the 7-day potential drift is 1.68 mV, which can respond normally to low frequency weak electric field signals at 1 mHz and 0.03 mV/m, and the response sensitivity and accuracy of the electrodes have been significantly improved. The electric field response performance of the electrically grafted modified carbon fibre electrode is comparable to that of the Ag/AgCl electrode. This is a new type of high performance marine electric field sensor, which is expected to improve the detection capability of marine electric fields.