Polyaniline-Modified Carbon Fiber Fabric Electrodes for Epoxy Resin-Based Multifunctional Structural Supercapacitor Composites

Abstract

Structural supercapacitors integrate energy storage with load-bearing capability, offering a route to reduce system weight and volume in multifunctional structures. Woven carbon fiber fabrics (WCF) are attractive structural electrodes because of their high mechanical strength and electrical conductivity, yet their low surface area and limited electrochemical activity constrain the charge storage. In this work, polyaniline nanofibers (PANI-NFs) are rapidly grown on WCF via in situ electrochemical polymerization to prepare PANI-NF@WCF electrodes, creating an electroactive nanofibrous interface that increases accessible surface area and provides pseudocapacitive charge storage. The PANI-NF@WCF electrode delivers an areal capacitance of 3.4 F cm⁻² at 1 mA cm⁻², markedly higher than that of pristine WCF electrode. Using these structural electrodes, an epoxy resin-based structural supercapacitor achieves an areal capacitance of 51.7 mF cm⁻² at 0.5 mA cm⁻², with a maximum energy density of 39.8 mWh kg⁻¹ and a power density of 3461.5 mW kg⁻¹. Three-point bending tests yield a flexural strength of 16.3 MPa and a flexural modulus of 1.9 GPa, demonstrating a practical balance between electrochemical performance and mechanical integrity. This study provides an efficient and facile electrode modification strategy for epoxy resin-based structural supercapacitor composites.