Freeze‐Tolerant Hydrogel Electrolyte with High Strength for Stable Operation of Flexible Zinc‐Ion Hybrid Supercapacitors. Issue 16 (10th March 2022)

• Record Type: Journal Article
• Authors: Zhu, Xiaoqing; Ji, Chenchen; Meng, Qiangqiang; Mi, Hongyu; Yang, Qi; Li, Zixiao; Yang, Nianjun; Qiu, Jieshan
• Is Part Of: Small. Volume 18:Issue 16(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-10
• Subjects: anti‐freezing -- hydrogel electrolytes -- mechanical performance -- zinc dendrites -- zinc‐ion hybrid supercapacitors; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202200055
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Constructing ionic conductive hydrogels with diversified properties is crucial for portable zinc‐ion hybrid supercapacitors (ZHSCs). Herein, a freeze‐tolerant hydrogel electrolyte (AF PVA‐CMC/Zn(CF3 SO3 )2 ) is developed by forming a semi‐interpenetrating anti‐freezing polyvinyl alcohol‐carboxymethyl cellulose (AF PVA‐CMC) network filled with the ethylene glycol (EG)‐containing Zn(CF3 SO3 )2 aqueous solution. The semi‐interpenetrating AF PVA‐CMC/Zn(CF3 SO3 )2 possesses enhanced mechanical properties, realizes the uniform zinc deposition, and impedes the dendrite growth. Notably, the interaction between PVA and EG suppresses the ice crystal formation and prevents freezing at −20 °C. Due to these advantages, the designed hydrogel owns high ionic conductivity of 1.73/0.75 S m −1 at 20/−20 °C with excellent tensile/compression strength at 20 °C. Impressively, the flexible AF quasi‐solid‐state ZHSC employing the hydrogel electrolyte achieves a superior energy density at 20/−20 °C (87.9/60.7 Wh kg −1 ). It maintains nearly 84.8% of the initial capacity after 10 000 cycles and a low self‐discharge rate (1.77 mV h −1 ) at 20 °C, together with great tolerance to corrosion. Moreover, this device demonstrates a stable electrochemical performance at −20 °C under deformation. The obtained results provide valuable insights for constructing durable hydrogel electrolytes in cold environments. Abstract : A freeze‐tolerant hydrogel electrolyte of anti‐freezing polyvinyl alcohol‐carboxymethyl cellulose/Zn(CF3 SO3 )2 with a semi‐interpenetrating network is developed, which possesses high ionic conductivity, superior mechanical strength, and excellent ability of dendrite growth inhibition. With these advantages, the AF zinc‐ion hybrid supercapacitor constructed with this hydrogel electrolyte exhibits a high energy density of 87.9/60.7 Wh kg −1 at 20/−20 °C and exceptional durability.