High-performance flexible and self-healable quasi-solid-state zinc-ion hybrid supercapacitor based on borax-crosslinked polyvinyl alcohol/nanocellulose hydrogel electrolyte

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 7; no. 46; pp. 26524 - 26532
• Main Authors: Chen, Minfeng, Chen, Jizhang, Zhou, Weijun, Xu, Junling, Wong, Ching-Ping
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 2019
• Subjects: Batteries; Borax; Cellulose; Crosslinking; Electrolytes; Energy storage; Hydrogels; Ion currents; Mechanical properties; Polyvinyl alcohol; Rechargeable batteries; Solid state; Supercapacitors; Work capacity; Zinc
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c9ta10944g

With the rapid development of wearable electronics, there arises an urgent need to exploit flexible, bendable, and even self-reparative energy storage devices. In order to realize this goal, one should construct suitable gel electrolytes. Herein, a zinc-salt-containing borax-crosslinked polyvinyl alcohol/nanocellulose hydrogel electrolyte is developed, and shows great mechanical properties, intriguing self-healing feature, and high ionic conductivity. To demonstrate the feasibility of this hydrogel electrolyte, a flexible quasi-solid-state zinc-ion hybrid supercapacitor is assembled from the hydrogel electrolyte, cellulose paper cathode, and zinc metal anode. This device can combine the advantages of both zinc-ion batteries and supercapacitors. It exhibits high capacity (56.1 mA h g −1 , 504.9 mF cm −2 , and 224.4 μA h cm −2 at 0.5 mA cm −2 ), great rate capability (22.1 mA h g −1 at 10 mA cm −2 ), and excellent cyclability (95.3% capacity retention over 5000 cycles). It can also be folded, bent, compressed, and even self-healed while sacrificing only a small portion of its capacity. This work opens the door to new possibilities in flexible energy storage. The quasi-solid-state zinc-ion hybrid supercapacitor based on borax-crosslinked polyvinyl alcohol/nanocellulose hydrogel electrolyte displays not only great electrochemical performances but also high flexibility and self-healing ability.