Low‐Temperature and High‐Voltage‐Tolerant Zinc‐Ion Hybrid Supercapacitor Based on a Hydrogel Electrolyte

Abstract

For flexible supercapacitors, adequate flexibility, a wide voltage window, and the ability to operate under ultralow temperatures remain a great challenge. In this study, a high-performance solid hydrogel (referred to as the PAM-SA-Ca 2 + hydrogel) with a tensile length reaching 2013.5 % and strong low-temperature tolerance was constructed. This ensured its stable structure at levels as low as À 75 °C . When it was used as the electrolyte in a flexible zinc-ion hybrid supercapacitor (ZHS), it could provide a wide operating voltage window of 0-2.2 V for ZHSs. Benefiting from these advantages, the ZHS device not only delivered a high specific energy (202.3 W • h • kg À 1 ), specific power (1048 W • kg À 1 ) and excellent cycling stability with capacity retention of 85.82 % after 11000 cycles, but it could also drive a timer at the ultralow-temperature of À 75 °C, emphasizing its great application potential as an advanced flexible electronic device.

Enhanced Mechanical Strength of Metal Ion-Doped MXene-Based Double-Network Hydrogels for Highly Sensitive and Durable Flexible Sensors

“…52−55 The first network is typically cross-linked by a covalent bond, which makes the hydrogel remain elastic under large strain. The second network can be cross-linked through coordination bonds between metal ions and SA, resulting in effective energy dissipation 56 and significant improvement of its mechanical properties. 57,58 However, there are few reports in the literature on the general strategy of using different metal ions to control the properties of MXene-based double-network hydrogels for flexible sensors.…”

“…Double-network hydrogels are a promising strategy to address the poor mechanical strength of MXene-based hydrogels. − They can be flexibly adjusted to tune mechanical properties such as stretchability, strength, and toughness by designing multiple intermolecular interactions to modulate the network structure. − The first network is typically cross-linked by a covalent bond, which makes the hydrogel remain elastic under large strain. The second network can be cross-linked through coordination bonds between metal ions and SA, resulting in effective energy dissipation and significant improvement of its mechanical properties. , However, there are few reports in the literature on the general strategy of using different metal ions to control the properties of MXene-based double-network hydrogels for flexible sensors. In particular, this strategy can significantly increase the strength of the hydrogel while sacrificing very little stretchability so that the hydrogel exhibits an elastic modulus suitable for human tissue.…”

A Hofmeister effect induced hydrogel electrolyte–electrode interfacial adhesion enhancement strategy for energy-efficient and mechanically robust redoxcapacitors

“…[9][10][11][12][13][14] However, the ZHSCs accommodate unsatisfying energy density compared to batteries, mainly due to the commonly used cathode materials (such as carbonaceous materials and conductive polymers) featuring typically low specic capacity associated with the adsorption/desorption manners and/or the surcial redox behaviors during the ion storage process. [15][16][17][18][19][20] Furthermore, the non-faradic/surface-faradic charge storage characteristics of the capacitor-type cathode also account for the typical linear timeoutput voltage response of the ZHSCs. Such an output voltage nature results in the instability issue of the continuously highpower output of the ZHSCs.…”