Carbon fiber tow incorporated with carbon slurry for structural power composite electrodes

Structural power composites are multifunctional materials that store electrical energy while supporting mechanical loads. Herein, we present mechanically robust and electrochemically high-performance electrodes for structural power composites, achieved by incorporating a carbon slurry into a carbon fiber (CF) tow. The carbon slurry consisted of activated carbon as the active material for electrochemical double-layer charging, carbon black as the electrical path, and polyvinylidene fluoride (PVDF) as the binder that are typical components used in double-layer supercapacitors. N-methyl-2-pyrrolidone (NMP) was used as the solvent. The composition of the carbon slurry was adjusted to evaluate the bond strength between the electrode materials and CFs using peel tests, followed by evaluation of the specific capacitance per unit weight of the corresponding electrode materials using cyclic voltammetry. The CF electrodes were fabricated by adjusting the amount of the NMP solvent in the slurry to ensure a high electrode material content while achieving uniform infiltration and coating of the slurry components within the CF tow. The electrodes were used to fabricate structural supercapacitors by coating them with polyvinyl alcohol (PVA) gel electrolytes containing potassium acetate and then sandwiching two such electrodes. The fabricated supercapacitors exhibited a specific capacitance of 24 F g⁻¹ and a tensile strength of ∼390 MPa. In addition, series and parallel connections of the supercapacitors were demonstrated to demonstrate the scalability of the electrodes in terms of voltage and power output.