Conventional hydrogel electrolytes containing conductive fillers have been widely used for energy storage devices due to the superb flexible and foldable characteristics. However, conductive fillers also cause the structural and chemical mismatches with polymer networks and hydrophilic water, thus compromising the mechanical and electrochemical properties of hydrogel electrolytes. It still remains a great challenge to achieve both excellent mechanical property and high ionic conductivity in the same hydrogels. In this work, we designed and synthesized a strong, double-network polyzwitterionic electrolyte by introducing water-soluble ionic liquid (EMIM-BF4) into zwitterionic hydrogels through the superfast solvent exchange. The resulting polyzwitterionic electrolytes are superior to traditional polyzwitterionic hydrogels or polyvinyl alcohol (PVA) hydrogels, as evidenced by high tensile strength (1.9 MPa), high ionic conductivity (7.24 mS/cm), and large temperature adaptability (-60~50 oC). More importantly, we used this ionogel electrolytes to fabricate the highly symmetric assembled supercapacitors, with high areal capacitance of 227.7 mF/cm2 at 0.5 mA/cm2, excellent rate capability, and high energy/power densities. We also implanted this polyzwitterionic electrolyte system to subcutaneous tissue of rats for better monitoring Physiological changes in mice via potential “on–off” variation of fault indicator LED. This work provides a new design strategy and a hydrogel system with improved mechanical and conductive properties for different supercapacitor applications under harsh environments.

Polyzwitterionic double-network ionogel electrolytes for supercapacitors with cryogenic-effective stability

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.