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

Abstract

AbstractFor 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‐Ca2+ 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 −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−1), specific power (1048 W ⋅ kg−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 −75 °C, emphasizing its great application potential as an advanced flexible electronic device.