Synergistic effects of chloride anions and carboxylated cellulose nanocrystals on the assembly of thick three-dimensional high-performance polypyrrole-based electrodes

Porous three-dimensional (3D) structures generally improve the performance of electrodes by increasing their active surface area and the diffusion speed of electrolyte ions during charging/discharging. Threedimensional polypyrrole (PPy) based films were created by electrodepositing PPy in the presence of varying amounts of chloride anions (Cl-) and polyanionic ribbonlike nanoparticles (carboxylated cellulose nanocrystals (CNC-COO-)) as scaffold material. The assembly mechanism of the 3D PPy electrodes combines the effect of different nucleation and growth mechanisms during electropolymerization and deposition of the formed PPy with CNC-COO- and with Cl-. The highest area capacitance of these electrode materials was 1.39 F cm(-2) (150.2 F g(-1)) at a current density of 1 mA cm(-2) (0.1 A g(-1)). More importantly, at a high current density of 20 mA cm(-2) (2.2 A g(-1)), the thick (ca. 130 lm), 3D, and high mass loading (9.2 mg cm(-2)) Cl-:CNC-COO-/PPy films exhibited an excellent areal capacitance of 0.85 F cm(-2) (70.8 F g(-1)), increasing about 16% over CNC-COO-/PPy films prepared without Cl- present during electrodeposition. In addition, an aqueous Cl-:CNC-COO-/PPy (with Cl-:CNC-COO- = 2.0) symmetric supercapacitor had an outstanding energy density of 41.15 lWh cm(-2) (4.46 Wh kg(-1)) and excellent cycling stability, while even improving on its original areal capacitance (to 111.2% of its original capacitance) after cycling 3000 cycles at 8 mA cm(-2), indicating their potential in energy storage devices. (c) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

Three-dimensional polypyrrole (PPy) electrodes were prepared using electrodepositing method with chloride anions and polyanionic ribbonlike nanoparticles as scaffold material. The highest area capacitance was 1.39 F cm2 and the electrodes exhibited excellent areal capacitance under high mass loading.