64 / 2023-12-29 10:40:17

HEDP Doped Conductive PANI/LS Composite Hydrogel Electrodes toward High Energy Density Flexible Supercapacitors

polyaniline, lignosulfonate, supercapacitors, electrochemical properties

7、矿物与先进能源材料 > 5、新能源材料与器件

Conductive polymer hydrogels applied in flexible supercapacitors(FSC) generally contain non-conductive matrix components (such as polyvinyl alcohol, polyacrylamide, etc.), which have a certain negative impact on the electrode conductivity and electrochemical performance. Herein, conductive polymer composite hydrogels without gel matrix were synthesized via direct polymerization of aniline (ANI) in Sodium lignosulfonate(LS) aqueous solution, for which Hydroxyethanediphosphonic acid(HEDP) was employed as an organic doping acid. The as-prepared polyaniline (PANI)/HEDP/LS(PHL) composite hydrogel electrodes exhibit a specific capacitance of up to 625 F g⁻¹ at 0.5 A g⁻¹, satisfactory long-term cycling stability (76.51% capacitance retained after 10,000 charge/discharge times), and outstanding flexibility (92.64% capacitance retained over 200 repeated bends), and the incorporation of HEDP enhanced electrochemical performances of PHL composite hydrogel electrodes. Besides, the synergistic effects offered by pseudocapacitance of PANI, the doping effect of HEDP and the redox reaction of phenolic hydroxyl groups in Sodium lignosulfonate may further contribute to the excellent electrochemical behavior of hydrogel electrodes. The result of the energy storage mechanism implied that the electrochemical process of the PHL composite hydrogel electrode involved both diffusion-controlled and surface capacitive processes. The all-hydrogel-state FSC based on the PHL hydrogel electrode shows a favorable energy density of 22.5 W h kg⁻¹ at 125.0 W kg⁻¹ as well as long-life stability of 80.75% capacitance retention after 10,000 charge/discharge cycles. This work is promising for the preparation of high-performance composite hydrogel electrodes for wearable and flexible energy storage devices.