3D‐Printed Ultrahigh‐Conductivity Polymer Gel Electrodes with High Mass Loading for Thickness‐Independent Zinc‐Ion Hybrid Micro‐Supercapacitors
Jian Meng, Zhenjiang Tan, Wei Zong, Wei Fan, Yang Chen, Chao Zhang, Le Li, Tianxi Liu
Abstract
Abstract Simultaneously achieving high mass loading and uncompromised capacitance performance represents a critical challenge for advancing zinc‐ion hybrid micro‐supercapacitors (ZHMSCs) toward practical applications. This study addresses this fundamental limitation by developing direct ink writing (DIW) 3D‐printed Zn 2+ ‐poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate/MXene (Zn‐PM) gel electrodes for high mass loading ZHMSCs. Synergistic PEDOT:PSS/MXene interactions enable formulation of high‐concentration viscoelastic printable gel inks, yielding thick gel electrodes with ultrahigh mass loading (32.2 mg cm −2 ) and high shape fidelity via precise 3D printing. Rationally engineered Zn‐PM gel electrodes undergo phase separation, complete PSS removal, and PEDOT electronic structure transition through MXene doping, Zn 2+ coordination, and freeze–thawing processing, thereby constructing 3D continuous conducting networks with ultrahigh conductivity (2326 S cm −1 ) and hierarchical porous architectures with accelerated rapid ion transport kinetics. The fabricated quasi‐solid‐state ZHMSCs, integrating 3D‐printed Zn‐PM gel cathodes and electrodeposited Zn nanosheet anodes, exhibit a groundbreaking areal capacitance of 2179 mF cm −2 and energy density of 333.6 µWh cm −2 with thickness‐independent energy storage characteristics, outperforming current state‐of‐the‐art zinc‐ion hybrid capacitors. This work provides a new paradigm for engineering ultrahigh mass‐loading micro‐energy storage devices via synergistic integration of rational electrode architecture engineering and advanced 3D printing fabrication strategies.