Redox‐Mediated Poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid)/Ammonium Molybdate Hydrogels for Highly Effective Flexible Supercapacitors

Abstract

Flexible supercapacitors were constructed by using novel redox-mediated polymer electrolytes including poly (2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) and ammonium molybdate [(NH 4 ) 2 MoO 4 ] (Mo). The gel polymer electrolytes PAMPS/Mo x were prepared in different compositions, where x represents the doping ratio of Mo into PAMPS electrolyte. The structure and morphology of the electrolytes were elucidated by using various spectroscopic and microscopic methods, and then they were used in the fabrication of symmetric supercapacitors. The electrochemical performances of the devices were investigated by using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectro-scopy. The system containing active carbon as the electrode and PAMPS/Mo 3 as the electrolyte produced a maximum specific capacitance of 530 F g À 1 with a 30 % enhancement in capacitance compared to the Mo-free supercapacitor. The energy density of the device is 73 Wh kg À 1 with a power density of 580 W kg À 1 . The redox-active hydrogel-based supercapacitor exhibited an excellent performance even after 2500 chargedischarge cycles, maintaining 92 % of its original capacitance. A flexible supercapacitor was assembled by using PAMPS/Mo 3 electrolyte and successfully operated a light-emitting diode (LED). microscopy (TEM) to obtain the detailed morphology of the PAMPS/Mo x . For TEM sample preparation, a small amount of material was dispersed in ethanol by sonication. The sample dispersions were then deposited onto TEM grids. The grids, then dried and examined under TEM (FEI, Morgagni 268) at 80 kV.Supercapacitor devices were fabricated using the configuration: Electrode/Hydrogel-Mo/Electrode. The PAMPS hydrogel was used directly with Mo as additive. The Cyclic voltammetry (CV) and galvanostatic charge-discharge (CD) experiments were carried out using GPE in carbon-based supercapacitors. The configured devices were placed into the Swagelok cell kit and attached to MTI Battery Analyzer. GCD analysis was done at different current densities ranging from 0.5 to 10 A g À 1 and cut off voltage was set between 0.1 to 1 V. The supercapacitor cell was then assessed at different scan rates ranging from 10 to 400 mV s À 1 . Cyclic voltammetry (CV) of the devices was investigated by using Palmsense emstat-3 electrochemical analyzer.

Highly Strong and Tough Double‐Crosslinked Hydrogel Electrolyte for Flexible Supercapacitors

“…[17] Ayhan and co-workers prepared hydrogel electrolytes with excellent electrochemical properties by introducing ammonium molybdate into PAMPS and poly (vinylphosphonic acid) (PVPA). [18][19][20] Recently, we reported a hydrogel electrolyte based on hydrophobic association interaction. [21] the electrolyte shows better mechanical properties and ion transport ability.…”

“…Dai prepared a polyacrylamide−chitosan‐based Water‐in‐salt electrolytes with high ionic conductivity (51.3 mS cm −1 ) and operating voltage (2.6 V) and excellent flexibility and self‐healing ability . Ayhan and co‐workers prepared hydrogel electrolytes with excellent electrochemical properties by introducing ammonium molybdate into PAMPS and poly (vinylphosphonic acid) (PVPA) …”

Construction of symmetric supercapacitors using anhydrous electrolytes containing heterocyclic oligomeric structures

“…The fabrication of the supercapacitor was achieved by mixing the optimized fractions (w/w) of 10% CC, 10% PVDF, and 80% active carbon (CA) . Primarily, the dissolving of PVDF in NMP at 70°C followed by adding activated carbon and CC slowly into the solution.…”

“…GPEs are fabricated by immobilizing liquid electrolytes in host polymer networks, which could provide high ionic conductivity, wide electrochemical potential window, minimized leakage, flexibility, mechanical integrity and stability, lightweight, and enhanced safety . Solid‐state GPEs have been fabricated and applied in electrochemical capacitors by using various polymer host networks such as poly‐(vinylidenefluoride‐ co ‐hexafluoro‐propylene), sulfonated polysulphone, poly(acrylonitrile), chitosan, poly‐(methylmethacrylate), poly(ethylene oxide), cellulose, and poly(vinylidene fluoride)–hexafluoro‐propylene copolymer …”

Design of high‐performance flexible symmetric supercapacitors energized by redox‐mediated hydrogels including metal‐doped acidic polyelectrolyte

“…On the other hand, batteries can provide higher energy density (30‐300 Wh kg −1 ) but lower power output (1 kW kg −1 ) and lower cycle lifetime . The storage mechanisms of supercapacitors are the key parameter where can be either electrical double‐layer (EDLC) formation at the electrode‐electrolyte interface or electrochemical reactions of active units in the redox electrolytes . Fast ion electrosorption promotes and accomplishes electrical double layer formation.…”