Surface engineering of reclaimed carbon fiber (RCF) electrode for superimposed supercapacitor performance

Abstract

Micrometer-sized carbon fiber (CF) has the advantage in directly serving as flexible electrode or support, while it simultaneously has the disadvantage of the unsatisfactory specific capacitance because of the small specific surface area and low activation. In this work, aerobically reclaimed carbon fiber (RCF) obtained from carbon fiber reinforced polymer (CFRP) is chosen as the subjected electrode, which is surface engineered through a thermal etch process of Cu2O/CuO anchored during a previous hydrothermal process and a subsequent chemical oxidation progress. Due to the circular holes as well as oxygen-containing functional groups on the functionalized CF surface, a superimposed electrochemical performance of functional holey reclaimed carbon fiber (FHRCF) electrode exhibits a specific capacitance of 122.2 F/g at 1 A/g (vs. 0.27 F/g for virgin CF, 31.3 F/g for RCF), and the capacitance retention of 100% after 30,000 cycles. Referring to its symmetrical supercapacitor (SSC), an energy density of 3.84 Wh/kg at the power density of 93.8 W/kg are acquired. This work not only pushes the reclamation of carbon fiber but also supplies μm-scale carbon fiber-based supercapacitor electrode with superimposed electrochemical performance.