Abstract: The electrochemical properties and electric field response of carbon fiber are improved significantly by introducing oxygen- and nitrogen-containing functional groups on the carbon fiber surface. Glutamic acid, glycine and lysine are grafted onto the surface of carbon fiber as the carrier of oxygen- and nitrogen-containing functional groups. The carbon fiber surface is characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The electrochemical properties and electric field response performance of carbon fiber surface are studied from the cyclic voltammetry curve, electrochemical impedance spectrum and electric field response curve. The results show that the modified carbon fiber electrode has larger electric double layer capacitance and lower low-frequency capacitive reactance; the average daily drift of potential difference between paired carbon fiber electrodes is less than 5 mV/d, and the electrochemical self-noise is less than 5 nV/Hz; and the modified paired carbon fiber electrode can better respond to 1 mV and 1 mHz sinusoidal electric field signal, and the linearity of modified glutamic acid group is 0.058%, which is the lowest among the modified groups. These results are much related to its special electric double-layer structure.

Key words: carbonfiberelectrode, aminoacidmodification, electrochemicalproperty, electricfieldresponseperformance