Stretchable supercapacitor based on a hierarchical PPy/CNT electrode and hybrid hydrogel electrolyte with a wide operating temperature

Abstract

Hydrogel is frequently used as a solid electrolyte for all solid‐state supercapacitors (SCs) because of its liquid‐like ion‐transport property and high conformability. However, due to the higher water content, the hydrogel electrolyte undergoes inevitable freezing and/or dehydration with climate change. Herein, polypyrrole/carbon all‐solid‐state SCs (PCSCs) were developed based on a hierarchical polypyrrole/carbon nanotube electrode and a highly stretchable double‐network polymer hydrogel electrolyte with LiCl/ethylene glycol as a mixed solvent. The PCSCs showed excellent electrochemical performance and cycle stability with a wide operating temperature. The specific capacitances could reach 202.2 and 112.3 mF cm−2 at current densities of 0.5 and 3.0 mA cm−2, respectively. Meanwhile, the PCSCs showed outstanding mechanical properties in maintaining a high areal capacitance under deformations of bending and tension. The excellent water retention of the device also ensured the stable electrochemical performance of PCSCs in a wide temperature range (30–80°C), which could potentially represent a reliable application in various harsh environments.

Polyacrylate-graft-polypyrrole Copolymer as Intrinsically Elastic Electrodes for Stretchable Supercapacitors

“…After 4 h, PHEA- g -PPy was obtained as a black sheet (1.5 cm × 1 cm × 0.33 mm, 0.329 g). The absorption of the N–H stretching vibration in the FT-IR spectrum of PHEA- g -PPy (Figure S4) shifted from 3392 to 3422 cm –1 due to the doping of p TSA . The graft ratio, defined as the weight proportion of grafted PPy in PHEA- g -PPy, was 42.7 wt %.…”

Flexible Polymer Hydrogels for Wearable Energy Storage Applications

“…By choosing the correct type of precursor/monomer, polymer hydrogels can be designed to have the main structural, mechanical, and energy storage properties required for different wearable energy storage applications including high conductivity under strain (poly(3,4ethylenedioxythiophene)):poly(styrene sulfonate) hydrogels can present a high electrical conductivity of 50 000 S m −1 ), [8b] high stretchability (polyaniline/polyurethane hydrogels can have a strain of 1150%), [68] high specific capacitance (polypyrrole hydrogels have a capacitance of 400 F g −1 at 0.2 A g −1 ), [7b] high capacitance retention after mechanical deformations (lignin-based hydrogels have an energy density of 13.7 Wh kg −1 at the power density of 201.4 W kg −1 after 5000 charge/discharge cycles), [16n] mechanical properties similar to skin and organs for the design of wearable and implantable electronics (polyacrylamide hydrogels have Young's moduli of 80 kPa and an ultrasoft tissue-like structure), [69] etc. Acrylic acid, [70] vinyl-pyrrolidine, [71] aniline, [16a] acrylamides, [69] polypyrrole, [72] and polyvinyl alcohol (PVA), [73] are just some of the common monomers/polymeric precursors that can be used to fabricate conductive/highly stretchable electrode/electrolyte hydrogels for energy storage applications. In addition to conventional monomers/precursors, polymer hydrogels can be synthesized from cationic and anionic monomers called polyampholytes, to have randomly distributed cationic Figure 3.…”

“…Acrylic acid, [ 70 ] vinyl‐pyrrolidine, [ 71 ] aniline, [ 16a ] acrylamides, [ 69 ] polypyrrole, [ 72 ] and polyvinyl alcohol (PVA), [ 73 ] are just some of the common monomers/polymeric precursors that can be used to fabricate conductive/highly stretchable electrode/electrolyte hydrogels for energy storage applications. In addition to conventional monomers/precursors, polymer hydrogels can be synthesized from cationic and anionic monomers called polyampholytes, to have randomly distributed cationic and anionic repeating units in the solid backbone of polymer hydrogels.…”

Physicochemical Modeling of Electrochemical Impedance in Solid-State Supercapacitors

“…Most of the EC models used in the study of supercapacitors are based on the mathematical approach (see, for example, [ 36 , 37 , 38 , 39 ]). However, in the current study, mathematical and physicochemical modeling approaches were individually applied to simulate the EIS response of an SSC, manufactured from biologically based carbon electrodes and gel-polymer electrolyte.…”