Engineering Self-Adhesive Polyzwitterionic Hydrogel Electrolytes for Flexible Zinc-Ion Hybrid Capacitors with Superior Low-Temperature Adaptability

Abstract

Flexible zinc-ion hybrid capacitors (ZIHCs) based on hydrogel electrolytes are an up-and-coming and highly promising candidate for potential large-scale energy storage due to their combined complementary advantages of zinc batteries and capacitors. However, the freezing induces a sharp drop in conductivity and mechanical property with tremendous compromise of the interfacial adhesion, thereby severely impeding the low-temperature application of such flexible ZIHCs. To achieve the flexible ZIHCs with excellent low-temperature adaptability, an antifreezing and self-adhesive polyzwitterionic hydrogel electrolyte (PZHE) is engineered via a self-catalytic nano-reinforced strategy, affording unparalleled conductivity and robust interfacial adhesion, together with superhigh mechanical strength over a broad temperature ranging from 25 to −60 °C. Meanwhile, the water-in-salt-type PZHE filled with ZnCl2 can provide ion migration channels to enhance the reversibility of Zn metal electrodes, thus greatly reducing side reactions and extending the cycling life. With distinctive integrated merits of the water-in-salt type PZHE, the as-built ZIHCs deliver a high-level energy density of 80.5 Wh kg–1, a desired specific capacity of 81.5 mAh g–1, along with a long-duration cycling lifespan (100 000 cycles) with 84.6% capacity retention at −40 °C, even outperforming the state-of-the-art ZIHCs at room temperature. More encouragingly, the extraordinary temperature-adaptability for both electrochemical and mechanical performance under severe mechanical challenges is achieved for the flexible ZIHCs at extremely low temperature. Noticeably, the ZIHC is also capable of operating in an ice–water bath and vacuum. It is believed that this strategy makes contributions to inspire the design and application of high-performance PZHEs in fields of flexible and wearable electronics that can work in extremely cold environments.

Transparent, Self‐Adhesive, Conductive Organohydrogels with Fast Gelation from Lignin‐Based Self‐Catalytic System for Extreme Environment‐Resistant Triboelectric Nanogenerators

“…Limited reserves of fossil fuels and growing environmental concerns have spurred the vigorous development of energyharvesting electronics using green, natural, and renewable time-consuming polymerization process with the continuous energy input from heating or UV irradiation. [16,17] Thus, a substantial need is existed for anti-freezing and long-lasting moisturizing hydrogels by a fast and energy-efficient preparation strategy.…”

“…[ 14,15 ] In addition, conventional hydrogels suffer from a time‐consuming polymerization process with the continuous energy input from heating or UV irradiation. [ 16,17 ] Thus, a substantial need is existed for anti‐freezing and long‐lasting moisturizing hydrogels by a fast and energy‐efficient preparation strategy.…”

Harmonizing Graphene Laminate Spacing and Zinc‐Ion Solvated Structure toward Efficient Compact Capacitive Charge Storage

“…[ 25,27 ] As for aqueous ZIHC, the capacitive porous carbon cathode accumulate electric charge mainly depends on the electrostatic counter ion adsorption. [ 28 ] In addition, Zn 2+ tends to form into hexahydrate structure ([Zn(H 2 O) 6 ] 2+ ) with ion size expansion from 1.48 to 8.6 Å via intense Coulombic interacting with surrounding water molecules. [ 29,30 ] Due to the ion sieving effects, the inaccessibility of solvated [Zn(H 2 O) 6 2+ ] in micropores will result in a severe loss of space utilization.…”

Synergistic effects of B/S co-doped spongy-like hierarchically porous carbon for a high performance zinc-ion hybrid capacitor

“…13–16 Among various MIHCs, zinc-ion hybrid capacitors (ZIHCs) have been widely explored due to their high theoretical capacity (823 mA h g −1 ), low oxidation/reduction potential (−0.76 V), good compatibility with water, rich zinc source and excellent safety. 17–27…”