Ionically crosslinked conjugated polyelectrolyte hydrogels for conductive agent/binder-free pseudocapacitors

초록

We report ionically crosslinked, dual-conductive conjugated polyelectrolyte (CPE) hydrogels with intrinsic porosity. In this platform, the anionic, p-type CPE-K (self-doped) enhances electronic conduction, while the cationic CPE-Br (bearing quaternary ammonium bromide) facilitates unhindered anion transport from the electrolyte to accelerate faradaic kinetics. Electrostatic complexation between the oppositely charged CPEs suppresses dissolution in aqueous media, integrates their complementary functions, and enables a high-performance, durable pseudocapacitor cathode without added conductive agents (e.g., carbon black) or binders. In three-electrode system, the optimized 1:2 CPE-K:CPE-Br composition delivers a specific capacitance of 147.3 F g(-1), substantially exceeding those of the neat CPE-K and CPE-Br. The 1:2 composite maximizes mixed transport, retaining similar to 95% of its 1 A g(-1) capacitance even at 50 A g(-1), and exhibits a Warburg factor far below typical organic electrodes, indicating highly efficient ion diffusion. An asymmetric full cell with single-walled carbon nanotubes anode, operated without conductive agent, binder, or separator, achieves 182.9 F g(-1) with similar to 84% retention after 10,000 galvanostatic cycles and similar to 100% coulombic efficiency, reaching energy and power densities of 35.7 Wh kg(-1)/5977 W kg(-1) at 5 A g(-1). These figures surpass prior organic pseudocapacitors, positioning ionically crosslinked, dual-conductive CPE hydrogels as a versatile, scalable platform for rapid-charging, long-life organic energy storage.

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