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

电接枝双氰胺改性碳纤维海洋电场电极的制备及其电场响应性能研究

School of Materials Science and Engineering, Ocean University of China, Qingdao 266100, China

Received: 9 February 2023

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.

摘要

碳纤维电极表面氨基改性可以显著提高其电化学性能和电场响应性能。通过控制接枝电压(3, 5, 7)V, 在碳纤维表面接枝聚双氰胺薄膜调控电极/海水界面双电层结构和电化学性能。结果表明, 接枝电位越高, 碳纤维表面聚双氰胺薄膜越均匀, 电极双电层结构越稳定。其中CF-7V的综合性能最佳, 其比电容达到9.368 F·g^-1, 为空白组的31.6倍; 电荷转移电阻和低频容抗显著降低; 7天电位漂移量为1.68 mV, 可以正常响应1×10^-3 Hz, 0.03 mV/m的低频弱电场信号, 电极的响应灵敏度、准确度得到了显著提高。电接枝改性后碳纤维电极的电场响应性能与Ag/AgCl电极相当, 这是一种新型高性能海洋电场传感器, 可望提高海洋电场探测能力。