Flexible Supercapacitor Based on Organohydrogel Electrolyte with Long‐Term Anti‐Freezing and Anti‐Drying Property

Abstract

Hydrogel electrolytes have spurred the development of flexible energy storage devices by endowing them with liquid-like ion transport and solidlike mechanical elasticity. However, traditional hydrogel electrolytes always lose these functions in climate change because the internal water undergoes freezing and/or dehydration. In this work, a flexible supercapacitor (OHEC) is assembled based on the organohydrogel electrolyte (OHE) and activated carbon electrode material. The OHE is composed of PAMPS/PAAm doublenetwork hydrogel soaked from 4 m LiCl/ethylene glycol and exhibits good conductivities (1.9 and 22.9 mS cm −1 at −20 and 25 °C, respectively). The OHEC exhibits broad temperature adaptability (from −20 to 80 °C) and extraordinary resistance to mechanical damage (above 100 kg crushing). The OHEC avoids the polarization at low temperatures and retains 77.8% capacitance retention after storage at −20 °C for 30 days. Without extra sealed packaging, the OHEC maintains remarkable cycling stability (only 8.7% capacitance decay after 10 000 cycles) and retains 77.3% capacitance at 80 °C after 56 h. The outstanding anti-drying performance and improved interfacial compatibility of OHEC account for the good durability in the hightemperature environments. Additionally, other salts (such as LiClO 4 , NaCl, and KCl) with favorable solubility in ethylene glycol can also serve in OHEs for wide temperature range supercapacitors.

Full‐Temperature All‐Solid‐State Ti3C2Tx/Aramid Fiber Supercapacitor with Optimal Balance of Capacitive Performance and Flexibility

“…[33] Also, the exfoliated F-MMT is common inorganic flame retardant, it can significantly reduce the peak heat release rate (PHRR) during polymer combustion. [34][35][36][37][38] However, because bulk MMT exhibits small specific surface area and few active sites (Figure S6a, Supporting Information), [34] it must be exfoliated into F-MMT by a freezing/thawing-ultrasonic method shown in Figure S6b in the Supporting Information, [35] and the detailed explanation is given in supporting information (Figure S6c-f, Supporting Information). To explain the role of F-MMT in F-MMT/PVA hydrogel, its morphology is analyzed by FE-SEM images.…”

An anti-freezing and anti-drying multifunctional gel electrolyte for flexible aqueous zinc-ion batteries

“…As shown in Fig. 2d, the exothermic peak in DSC curves represents the crystallization of the gel electrolyte, where the liquid phase in the gel electrolyte will transform into solid phase [59]. When the Gly volume content increases from 0% to 40%, the exothermic peak of gel electrolytes gradually shifts towards left, indicating the decrease of their freezing points [60][61][62].…”

Ultra‐Sensitive and Ultra‐Stretchable Strain Sensors Based on Emulsion Gels with Broad Operating Temperature

“…So the emulsion gel did not freeze and maintained conductivity at subzero temperature. Meanwhile, glycerol has low vapor pressure and high boiling point, which can reduce the volatilization of water molecules and endow the emulsion gel with anti‐drying ability [20] . Therefore, the emulsion gel did not dry out at high temperature and maintained conductivity after long time storage.…”

“…Meanwhile, glycerol has low vapor pressure and high boiling point, which can reduce the volatilization of water molecules and endow the emulsion gel with anti-drying ability. [20] Therefore, the emulsion gel did not dry out at high temperature and maintained conductivity after long time storage. On the contrary, hydrogel would lose its functions at low and high temperature.…”