Tunable Three-Dimensional Nanostructured Conductive Polymer Hydrogels for Energy-Storage Applications

Abstract

Three-dimensional (3D) nanostructured conducting polymer hydrogels represent a group of highperformance electrochemical energy-storage materials. Here, we demonstrate a molecular self-assembly approach toward controlled synthesis of nanostructured polypyrrole (PPy) conducting hydrogels, which was "cross-linked" by a conjugated dopant molecule trypan blue (TB) to form a 3D network with controlled morphology. The protonated TB by ion bonding aligns the free sulfonic acid groups into a certain spatial structure. The sulfonic acid group and the PPy chain are arranged by a self-sorting mechanism to form a PPy nanofiber structure by electrostatic interaction and hydrogen bonding. It is found that PPy hydrogels doped with varying dopant concentrations and changing dopant molecules exhibited controllable morphology and tunable electrochemical properties. In addition, the conjugated TB dopants promoted interchain charge transport, resulting in higher electrical conductivity (3.3 S/ cm) and pseudocapacitance for the TB-doped PPy, compared with PPy synthesized without TB. When used as supercapacitor electrodes, the TB-doped PPy hydrogel reaches maximal specific capacitance of 649 F/g at the current density 1 A/g. The result shows that PPy nanostructured hydrogels can be tuned for potential applications in next-generation energy-storage materials.

Incorporating Ni-MOF structure with polypyrrole: enhanced capacitive behavior as electrode material for supercapacitor

“…EIS is a critical technique to study the internal resistance of the electrode and the resistance between the electrode and electrolyte. The equivalent series resistance (ESR) is obtained from the rst intersection with the real axis 40,41. EIS measurements(Fig.…”

Highly Conductive, Stretchable, Adhesive, and Self‐Healing Polymer Hydrogels for Strain and Pressure Sensor

“…In PAA‐TB‐PPy hydrogel, the TB was not only used for a dopant but also acts as a crosslinker as the electrostatic and hydrogen bonding interaction between TB and PPy. [ 18 ] The possible structure between PAA‐TB‐PPy hydrogels are shown in Figure S1 in the Supporting Information. In the PAA‐TB‐PPy hydrogel system, in addition to the related interactions between PAA and TB, PPy chain is mainly bound through hydrogen bonding and electrostatic interactions with amino groups and sulfonic acid group on TB and hydrogen bonding with carboxyl groups on PAA.…”

“…reported a molecular self‐assembly approach toward controlled synthesis of nanostructured PPy hydrogels, in which TB was used as a physical crosslinking agent, it was found that the TB‐doped PPy hydrogel demonstrated excellent electrochemical performance for energy storage application. [ 18 ] However, related studies about TB used in electrochemical fields are still limited.…”

Properties of conductive polymer hydrogels and their application in sensors

“…The polymers that made up CPHs mainly include poly(3,4ethylenedioxythiophene) (PEDOT), polythiophene (PTh), polypyrrole (PPy), and polyaniline (PAni), which form into CPHs by constructing covalently or physically crosslinked hydrophilic network . CPHs, synergizing the advantages of hydrogels and organic conductors, exhibit unique electrical, chemical, and mechanical properties, which endow CPHs great potentials in energy storage device, tissue engineering, and different types of sensors …”