Sodium polyacrylate hydrogel electrolyte: Flexible rechargeable supercapacitor using thermally reduced graphene oxide nanosheets

• Published in: Journal of power sources 2025-01, Vol.625, p.235648, Article 235648
• Main Authors: Ali, Noor Ul Haq Liyakath, Pazhamalai, Parthiban, Sathyaseelan, Arunprasath, Swaminathan, Rajavarman, Kim, Sang -Jae
• Format: Article
• Language: English
• Subjects: Crosslinking; Sodium polyacrylate hydrogel; Solar charging power system; Supercapacitor; Thermally reduced graphene oxide
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2024.235648

The alternative source of the gel polymer electrolyte (GPE) is introduced by developing the sodium polyacrylate (S-PANa) solid hydrogel electrolyte, which is the front runner in the recent flexible and wearable electronic devices due to their excellent mechanical property, high ionic conductivity, and electrochemical stability. In this work, we synthesized the S-PANa solid hydrogel electrolyte and utilized it for the flexible symmetric supercapacitor using thermally reduced graphene oxide nanosheets (TRGO) coated on carbon cloth as an electrode. The prepared S-PANa hydrogel is of a highly porous nature and has better surface roughness, as examined by the Field Emission Scanning Electron Microscopy (FE-SEM) and 3D nano profiler analysis. The electrochemical characterization of the assembled flexible solid-state hydrogel supercapacitor (FSHSC) reveals the electric double-layer capacitive behavior with an excellent device capacitance of 45.77 mF/cm2. The significant role of diffusion charge re-distribution, overcharging issues, ohmic drop, and leakage current of the FSHSC is studied, followed by self-discharge and leakage current analysis. Moreover, the FSHSC device delivers the maximum energy density of 5.15 μWh/cm2 with a remarkable retention capacitance of 99 % over 10,000 continuous cycles. Further, in practical utilization, the solar-charged FSHSC device can effectively power the electronic LED for a long duration and enhance its efficiency for the development of a sustainable backup power system. Overall, these experimental results demonstrated the significant use of the S-PANa hydrogel-based flexible device, which can be an alternative source in future energy storage systems instead of using gel electrolyte-based flexible devices. [Display omitted] •The S-PANa hydrogel was prepared using a simple free radical polymerization process.•S-PANa-LiCl hydrogel was utilized as a separator-electrolyte in the supercapacitor.•The FSHSC device delivers the maximum device capacitance of 45.77 mF/cm2.•FSHSC achieved a remarkable energy density of 5.15 μWh/cm2.•The ability to power up electronic devices has been demonstrated using FSHSC.