Supported Ionic Liquid Gel Membrane Electrolytes for Flexible Supercapacitors

Abstract

In this work, a novel and easy‐to‐use methodology is developed to prepare supported ionic liquid gel membranes (SILGMs) by incorporating ionogels into commercial porous supports, to use as both electrolytes and separators for supercapacitors. Macroscopic sol–gel transition temperature, Fourier transform infrared spectra, and thermal behaviors of the ionogels are systematically investigated. Ionic conductivities of the ionogels and SILGMs are measured from 25 to 100 °C. The ionic conductivities of the ionogels are lower by one order of magnitude once they are incorporated into the supports. Nonetheless, the ionic conductivity of the SILGMs has reached the practical application level required for energy storage and conversion devices. Furthermore, the stability and flexibility of SILGMs are investigated as flexible electrolytes for supercapacitor devices (see Video in the Supporting Information). Charge–discharge cycling of symmetric supercapacitors based on the SILGMs reveal specific capacitance as high as 153 F g−1 at 0.1 A g−1, and remain at 101 F g−1 at 10 A g−1. The capacitance retention after 10 000 charge–discharge cycles at 5.0 A g−1 is as high as 97%, demonstrating excellent cycle stability of the device. The studies suggest that SILGMs are promising candidates for stable, high performance, and flexible energy storage and conversion devices that could be made by high volume roll‐to‐roll processing.

All‐Solid‐State Fiber Supercapacitors with Ultrahigh Volumetric Energy Density and Outstanding Flexibility

“…[34][35][36][37][38] Indeed, various ILs have been studied for flexible SCs based on carbon materials and transition metal oxides/ nitrides, which allows for the expansion of their maximum cell voltage (up to 3.2-3.5 V), and consequently the improvement of their maximum energy/power density. Ionic liquids (ILs), normally consist of organic cations and anions, are promising electrolytes that can enhance the performance of SCs owing to their wider electrochemical windows, high ion conductivity, high thermal stability, and nonflammability.…”

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

“…The ESR resistances of PVPA/Ni1, PVPA/Ni3, PVPA/Ni5, and PVPA/Ni10 device electrodes were obtained as 0.31, 0.59, 1.31, and 2.40 Ω, respectively. The Warburg resistance (W) of the system indicates the ion diffusion through the pores on the electrode surface in the low frequency region . The W of all devices demonstrates that the AC‐PVPA/Ni system generates high CD performance by allowing maximum ion diffusion at the electrode level.…”

“…The energy density is indicated by E , the power density by P , the voltage window by Δ V and the discharge time Δ t …”

Stretchable Supercapacitors as Emergent Energy Storage Units for Health Monitoring Bioelectronics

“…[42,76] For example, a highly stretchable H 3 PO 4 /PVA polymer electrolyte coupled with electrode of conductive polymer, namely polypyrrole, was reported, which showed an excellent fracture strain at 410% elongation and a high conductivity of 3.4 × 10 −3 S cm −1 . [85][86][87] Advances in hydrogel engineering also offer the opportunity to develop versatile gel electrolytes with additional features such as healability, biocompatibility, and transparency, [88][89][90][91][92] which can be valuable in some health monitoring context. Thereafter, various polymer matrixes have been utilized, including PMMA, PAA, PEO, PAM, and PVDF, [66,[78][79][80] and electrolytic salts such as KOH, LiCl, and LiClO 4 have also shown utility as the ion source.…”