Chlorogenic Acid-Modified MXene/PEDOT:PSS Composite Ink for Stable and High-Performance Textile Supercapacitor Electrodes

Textile-based supercapacitors hold great promise for wearable energy storage, yet the oxidative instability of MXene electrodes and the poor interfacial adhesion between conductive materials and fabric substrates remain critical bottlenecks. Herein, we report a multifunctional composite electrode fabricated by spray-coating a MXene@CGA/PEDOT:PSS (MCP) composite ink onto amino-modified cotton fabric (AMCF). Ti3C2Tx MXene was first surface-modified with chlorogenic acid (CGA), a natural polyphenolic antioxidant that forms covalent and hydrogen bonding interactions with MXene surface terminations, expanding the interlayer spacing from 1.226 to 1.319 nm and conferring exceptional oxidation resistance, with the MXene@CGA dispersion retaining its structural integrity after 30 days of accelerated aging at 60 °C. The MXene@CGA was subsequently integrated with PEDOT:PSS:EG to formulate the MCP composite ink, in which spontaneous PEDOT:PSS intercalation further expanded the interlayer spacing to 1.724 nm, while interfacial electron transfer promoted a polaron-to-bipolaron transition and benzoid-to-quinoid conformational change in PEDOT, synergistically enhancing charge delocalization and electrical conductivity. Cotton fabric was amino-functionalized via periodate oxidation and poly-L-lysine grafting to yield AMCF with abundant reactive surface groups, facilitating strong anchoring of the MCP coating. The resulting MCP-AMCF electrode delivered a high areal capacitance of 382.5 mF·cm-2 at 1 mA·cm-2, good rate capability, and 75.3% capacitance retention after 4000 cycles, with electrochemical performance remaining stable after 30 days of ambient storage. This work demonstrates a promising integrated strategy combining molecular antioxidant protection, conductive polymer intercalation, and covalent substrate functionalization for stable, high-performance wearable textile electrodes.