Enhancing Mechanical and Electrochemical Stability of EDLC Electrodes via Crosslinked Polysaccharide Binder Blends

ABSTRACT Advancing sustainable energy storage technologies has increased the focus on water processable binders for high‐performance battery and capacitor electrodes. In this work, a blend of potato starch (PS) and xanthan gum (XG) is chemically cross‐linked with four carboxylic acids (citric, malic, succinic, and glutaric) to improve the mechanical and electrochemical performance of the electric double‐layer capacitors (EDLCs) electrodes. Low‐temperature cross‐linking via esterification is confirmed by FTIR and TGA analysis, showing ester bond formation already at 80 °C. Mechanical characterization demonstrates that cross‐linked binders, particularly citric acid (PXC) and malic acid (PXM), significantly improve adhesion strength (up to 0.38 MPa for PXC) and reduce elastic deformation, correlating with increased cross‐linking density. Electrochemical tests demonstrate that PXC and PXM electrodes achieve superior capacitance retention at high current densities and long‐term floating voltage conditions. After 500 h at 3 V, cross‐linked electrodes retain over 91% of their initial capacitance, compared to 84% for the non‐cross‐linked reference. Electrochemical impedance spectroscopy further shows that cross‐linked binders display notably lower contact and interfacial resistances, even after long term floating test. This study highlights the potential of cross‐linked polysaccharide binders as a promising green binder system to enhance mechanical integrity and long‐term high voltage electrochemical stability of EDLC electrodes.