A double cross-linked hydrogel electrolyte with high mechanical strength and excellent electrochemical performance for flexible supercapacitor and zinc ion capacitor

• Published in: Journal of alloys and compounds 2022-10, Vol.918, p.165688, Article 165688
• Main Authors: Kuang, Shaojie, Huang, Zixuan, Huang, Yaoliang, Shao, Dan, Jia, Xinying, Feng, Baiyi, Yan, Yun, Hu, Hang, Yu, Xiaoyuan
• Format: Article
• Language: English
• Subjects: Biomass; Capacitance; Capacitors; Compressive properties; Compressive strength; Crosslinking; Electrochemical analysis; Electrolytes; Energy storage; Flexible; Gelatin; Hydrogel electrolytes; Hydrogels; Ion currents; Polyacrylamide; Supercapacitor; Supercapacitors; Tensile strain; Zinc; Zinc ion capacitor
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.165688

A biomass hydrogel electrolyte with double cross-linked structure was successfully fabricated by in situ polymerization and cross-linking reaction using polyacrylamide (PAAm) as the main network and gelatin as the reinforced network. This as-prepared gelatin/PAAm hydrogel electrolyte exhibits excellent mechanical strength (compressive, tensile strain and stress of GP-10 can reach 80 %, 1700 % and 10.4 MPa respectively) and high ionic conductivity. Flexible supercapacitors (FSCs) based on the gelatin/PAAm hydrogel electrolytes deliver a high specific capacitance of 140 F g−1 and excellent energy density of 49.8 Wh kg−1. More importantly, the FSCs not only achieve a long life of 50,000 cycles in a stable environment but also deliver high specific capacitance and good cycle performance when cycled at different folded angles. The constructed zinc ion capacitors (ZICs) applied with the gelatin/PAAm hydrogel electrolytes can achieve capacity retention of 98.0 % after 10,000 cycles at a high current density of 1 A g−1. These results demonstrate that the biomass hydrogel electrolytes exhibit excellent electrochemical performance and durability in flexible energy storage devices. [Display omitted] •A double cross-linked gelatin/PAAm hydrogel electrolyte is developed.•The hydrogel electrolyte has excellent mechanical properties and high ionic conductivity.•The constructed FSCs achieve high energy density of 49.8 Wh kg−1 at 0.16 kW kg−1 and long cycle life of 50,000 cycles.•ZICs display a high specific capacity of 61.9 mA h g−1 at 0.2 A g−1 and capacity retention of 98.0 % after 10,000 cycles.