Influence of Surface Chemistry on Carbon Fiber Structural Battery Anodes

Carbon fiber (CF) electrodes offer a promising route to enhance both mechanical and electrochemical performance in multifunctional structural batteries for future technologies such as electric vehicles, next‐generation aircraft, and autonomous satellites. Recent developments have focused on solid battery electrolytes that deliver both ionic conductivity and mechanical strength. Central to this is the CF interface, which plays a dual role in structural reinforcement and charge storage. While interfacial chemistry is well studied in composites, its impact on the anode performance of CFs tailored for mechanical performance remains unclear. This article explores how CF surface chemistry influences electrochemical battery performance, by grafting functional groups known to improve composite adhesion (NO 2 , NH 2 , SH, SO 3 H). Surface modifications are confirmed using scanning electron microscopy, Raman spectroscopy, and X‐ray photoelectron spectroscopy. Untreated CFs delivered an initial capacity of 189.1 ± 42.6 mAh g −1 , while SH‐ and NO 2 ‐functionalized CFs achieved enhanced capacities of 244.0 ± 12.1 and 243.8 ± 64.1 mAh g −1 , respectively. These results suggest that chemical surface modification—while originally intended for composite performance—may also improve the anode performance in structural battery systems.