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Acta Armamentarii ›› 2022, Vol. 43 ›› Issue (11): 2855-2865.doi: 10.12382/bgxb.2021.0569

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Electrochemical Properties and Electric Field Response of Electrically Grafted Polyethyleneimine Modified Carbon FiberElectrodes

XU Jiawei, HAN Yongkang, SUN Jiuzhe, FU Yubin   

  1. (School of Materials Science and Engineering, Ocean University of China, Qingdao 266000, Shandong, China)
  • Online:2022-05-22

Abstract: The electrochemical and electric field response properties of carbon fiber electrodes can be significantly enhanced through surface amine modification. In this paper, polyethyleneimine (PEI) of different molecular weights (0.6K,1.8K,10K) is grafted on the surface of carbon fibers by a combination of high-temperature oxidation with electrochemical grafting to modulate the bilayer structure at the electrode/seawater interface. It is found that longer molecular chains are more easily interspersed and overlapped for they have stronger hydrogen bonding interactions, resulting in a more stable electric bilayer structure. Therefore, PEI-10K shows the best performance with a specific capacitance of 12.8 F·g-1 and charge transfer resistance and low-frequency capacitive reactance significantly reduced. The potential drift of the paired electrode is only 0.05 mV/d. The self-noise of the electrode is reduced to 2.61 nV/sqrt (Hz) and can respond to the low-frequency weak electric field signal of 1 mHz and 0.03 mV/m. The response sensitivity and accuracy of the modified carbon fiber electrode have been significantly improved. This approach can be used to prepare high-performance marine electric field sensor and improve the detection ability of underwater electric field.

Key words: carbonfiberelectrode, polyethyleneimine, electrochemicalgrafting, electrochemicalperformance, electricfieldresponsecharacteristics

CLC Number: