Degradation of the Three-Phase Boundary Zone of Carbon Fiber Anodes in an Electrochemical System

The electrochemicalrecycling nanoarchitectonics of graphene oxidefrom carbon fiber reinforced polymers (CFRPs) is a promising approachdue to its economic and environmental benefits. However, the rapiddegradation of the CFRP anode during the recycling process reducesits overall efficiency. Although previous studies have investigatedthe electrochemical oxidation of carbon fibers (CFs) and bonding ofCFs to the matrix, few researchers have explicitly studied the electrochemicalactivity of CFs and the possible fracture caused by strong electrochemicalreactions. To address this gap, this study investigates the degradationmechanism of CF anodes by analyzing changes in overall mechanicalproperties, hardness, elastic modulus, functional groups, and elementalcomposition of individual fibers. The experimental results demonstratethat the three-phase boundary region experiences the most severe degradation,primarily due to the number of oxygen-containing functional groups,which is the most important factor affecting the degree of degradation.This continuous decrease in the hardness and elastic modulus of individualfibers eventually leads to the fracture of CF anodes.