53 / 2022-03-30 18:51:40

Electrochemical Realization of High-Performance Carbon Fiber as Electrode Materials for Cement-Based Systems

Carbon fiber, Oxidation treatment, Cl-, SO42-, Electrode materials.

Carbon Fiber (CF) is made of graphite wire with a diameter of about 5-10 µm, and it has the characteristics of high strength, large modulus, light-weight, strong alkaline corrosion resistance, and no toxicity. Recently, in the process of intelligent development of buildings, CF has been widely used in the field of construction. The electrochemical properties of CF can greatly affect its efficient application as electrode materials in construction (e.g. cement-based battery, cathodic protection). Currently, more than 90% of CF materials on the market are made from polyacrylonitrile (PAN), and these original CFs usually have poor electrochemical activity and low specific surface area. In this work, we have investigated the evolution of the surface states of PAN-based CF under electrochemical oxidation conditions in ordinary electrolytes and proposed a simple, low-cost, large-scale and environmentally friendly modification strategy to improve the surface electrochemical properties of CF. The experimental results show that CF exhibits different variations of the surface oxidation process and morphology under different ionic conditions (Fig. 1a). In the strongly alkaline solution of Cl^-, the content of oxygen-containing functional groups on the surface of CF increases, which leads to a remarkable enhancement of CF electrochemical activity (as shown in Fig. 1b). The treated CF can be used as a good anode material for the cathodic protection system of reinforced concrete in high chlorine environment. In the strong alkali solution of SO₄^2-, swelling and spalling of the carbon layers occur on the surface of CF, resulting in a remarkable increase of the specific surface area (as shown in Fig. 1c). The obtained CF with good capacitive properties can be used as electrode materials for cement-based battery devices. This study provides a simple method to improve the electrochemical properties of CF for efficient application as electrode materials in a strongly alkaline cement matrix.