An Antifreezing, Tough, Rehydratable, and Thermoplastic Poly(vinyl alcohol)/Sodium Alginate/Poly(ethylene glycol) Organohydrogel Electrolyte for Flexible Supercapacitors

Abstract

A hydrogel electrolyte is an ideal material for flexible energy storage equipment owing to its mechanical flexibility similar to solids and its ion transport ability analogous to liquids. However, a traditional hydrogel electrolyte cannot be remolded after forming and cannot be reused after dehydration. In addition, the traditional hydrogel electrolyte cannot work in a subzero environment. Here, the poly(vinyl alcohol)/sodium alginate/poly(ethylene glycol) (PVA/SA/PEG) organohydrogel electrolyte was successfully fabricated by a freezing−thawing process followed by soaking in a saturated NaCl aqueous solution. PEG could improve the mechanical property and endowed the organohydrogel with an excellent recyclability and healing ability. Meanwhile, PEG and NaCl in the organohydrogel also endowed the gel with lowtemperature resistance. A new solution was provided to store and transport hydrogels by virtue of the good rehydration properties after the drying process. The flexible all-solid-state supercapacitor was fabricated by using activated carbon as the electrode and PVA/SA/PEG as the gel electrolyte. The flexible supercapacitors presented high areal capacitances of 103.6 mF cm −2 at 2 mA cm −2 at room temperature and 91.5 mF cm −2 at −15 °C. It is believed that the PVA/SA/PEG organohydrogel electrolyte with outstanding flexibility, freezing resistance, recyclability, and high ionic conductivity is a promising candidate for the next-generation flexible energy storage devices.

A Highly Conductive, Self-Recoverable, and Strong Eutectogel of a Deep Eutectic Solvent with Polymer Crystalline Domain Regulation

“…It is well-known that poly­(vinyl alcohol) (PVA) possesses advantages of low toxicity, good biodegradability, and biocompatibility and is a good polymer skeleton material for a high-strength gel because its crystalline domains induced by dense hydrogen-bond interactions can provide abundant physical cross-linking points. − Therefore, a flexible sensor based on PVA is expected to be endowed with outstanding mechanical properties and an antifatigue capability. However, the traditional freezing–thawing method for preparing a PVA gel is time-consuming.…”

Synergistic Effect of Sodium Alginate and Lignin on the Properties of Biodegradable Poly(vinyl alcohol) Mulch Films

“…27 For PVA film preparation, cross-linking with glutaraldehyde 16 and citric acid 28 or addition of xylan, eggshell powder, 29 liquefied chitin, 30 starch, 31 chitosan, 32 or cellulose 33 natural polymers has shown to significantly improve tensile strength. However, the addition of chitosan and cellulose will reduce the elongation at break of the material, and the addition of citric acid-modified xylan 34 and SA 35 will reduce the tensile strength. However, the elongation at break will be enhanced accordingly.…”

Constructing Flexible All‐Solid‐State Supercapacitors from 3D Nanosheets Active Bricks via 3D Manufacturing Technology: A Perspective Review

“…[11,12] On the other hand, the development of hydrogel-based electrolytes (high flexibility and high security) and non-hydrogel-based electrolytes (high voltage window and low temperature resistance) with multiple characteristics (stretchable, self-healing, and compressible) is also critical for flexible all-solid-state supercapacitors. [13][14][15] Ultrathin 2D nanomaterials (including carbon-based and metallic nanosheet materials) with high specific surface area play an important role in improving the capacitance characteristics of supercapacitors. [16][17][18] However, during the electrode preparation process, the irreversible stacking of 2D nanosheets caused by van der Waals force, greatly reduces the available surface area and hinders the transport of electrolyte ions, which affects the specific capacitance and rate performance of electrode materials.…”

“…[ 11,12 ] On the other hand, the development of hydrogel‐based electrolytes (high flexibility and high security) and non‐hydrogel‐based electrolytes (high voltage window and low temperature resistance) with multiple characteristics (stretchable, self‐healing, and compressible) is also critical for flexible all‐solid‐state supercapacitors. [ 13–15 ]…”