A Flexible Stretchable Hydrogel Electrolyte for Healable All‐in‐One Configured Supercapacitors

Abstract

The development of integrated high-performance supercapacitors with all-in-one configuration, excellent flexibility and autonomously intrinsic self-healability, and without the extra healable film layers, is still tremendously challenging. Compared to the sandwich-like laminated structures of supercapacitors with augmented interfacial contact resistance, the flexible healable integrated supercapacitor with all-in-one structure could theoretically improve their interfacial contact resistance and energy densities, simplify the tedious device assembly process, prolong the lifetime, and avoid the displacement and delamination of multilayered configurations under deformations. Herein, a flexible healable all-in-one configured supercapacitor with excellent flexibility and reliable self-healing ability by avoiding the extra healable film substrates and the postassembled sandwich-like laminated structures is developed. The healable all-in-one configured supercapacitor is prepared from in situ polymerization and deposition of nanocomposites electrode materials onto the two-sided faces of the self-healing hydrogel electrolyte separator. The self-healing hydrogel film is obtained from the physically crosslinked hydrogel with enormous hydrogen bonds, which can endow the healable capability through dynamic hydrogen bonding. The assembled all-in-one configured supercapacitor exhibits enhanced capacitive performance, good cycling stability, reliable self-healing capability, and excellent flexibility. It holds broad prospects for obtaining various flexible healable all-in-one configured supercapacitors for working as portable energy storage devices in wearable electronics.

Compressible All‐In‐One Supercapacitor with Adjustable Output Voltage Based on Polypyrrole‐Coated Melamine Foam

“…[9][10][11][12] Recently, substantial effort has been devoted to endow flexible supercapacitors with more efficiency, more stability, and low cost in order to develop fully flexible electronics. [16][17][18][19] Compared with the common flexible supercapacitors with laminated structure, the major components of the all-inone flexible supercapacitors including two electrodes, separator, electrolyte, and current collectors are integrated on the same substrate. Generally, the common flexible supercapacitors exhibit a multilayer laminated configuration, which are fabricated by placing a gel electrolyte layer between two flexible electrodes.…”

“…Generally, the common flexible supercapacitors exhibit a multilayer laminated configuration, which are fabricated by placing a gel electrolyte layer between two flexible electrodes. [17] Wang et al integrated the electrode-electrolyte-electrode component in a free-standing poly(vinyl alcohol) chemical hydrogel film to fabricate an all-in-one supercapacitor. [20,21] This integrated design cannot noly reduce the contact resistance of the interface but also increase the mechanical durability including compression stability and stretching and/or twisting reliability.…”

“…[17] Wang et al integrated the electrode-electrolyte-electrode component in a free-standing poly(vinyl alcohol) chemical hydrogel film to fabricate an all-in-one supercapacitor. Guo et al reported healable supercapacitors with all-in-one configuration by in situ polymerization and deposition of single-walled carbon nanotube (SWCNT) and polyaniline (PANI) onto the two sides of the healable hydrogel electrolyte separator.…”

Conducting Polymers for Flexible Supercapacitors

“…The as‐fabricated “all in one” supercapacitor showed an areal capacitance of 15.8 mF cm −2 at a current density of 0.044 mA cm −2 . After the fifth self‐sealing cycles, up to 80% retention of the areal capacitance was obtained, implying a good self‐healable performance for the flexible “all in one” supercapacitors …”

“…Unfortunately, most of the reported self‐healing supercapacitors require auxiliary healable layer(s), which led to complicated assembly for the supercapacitors and a limited energy density . Recently, a self‐healable “all in one” flexible supercapacitor has been fabricated by in situ chemical deposition of PANI and single walled CNT (SWCNT) hybrid onto the two‐sided faces of healable PVA‐H 2 SO 4 hydrogel . Numerous hydrogen bonds embedded in the physically cross‐linked network of PVA allowed for self‐healing by the dynamic formation of hydrogen bonds after being damaged.…”