Ionogel Based Self-Healing, Air-Stable and Flexible Electronics

Hydrogels have been considered as one of the ideal materials for wearable electronics owing to its self-healing property as well as flexibility, transparency and ionic conductivity by adding ionic salts. However, such a good conductivity, mechanical and healing properties can be easily impaired due to the evaporation of water in hydrogels. On the other hand, ionogels typically consisting of ionic liquid and polymer network present a great potential in wearable devices due to a low vapor pressure of ionic liquid in addition to the high ionic conductivity.<br/>Here, we report on a self-healing, air-stable and flexible supercapacitor based on ionogels. Synthesized ionogel composite is prepared by polymerization of acrylic acid (AA) with N,N′-Bis(acryloyl)cystamine (BACA)-modified Au nanoparticles (AuNP) as chemical crosslinkers adding lithium perchlorate and 1-Ethyl-3-methylimidazolium ethyl sulfate as solvent. The synthesized poly(acrylic acid)/AuNP@BACA (PGB) ionogel exhibits a high stretchability up to 500%, good ambient air stability and high self-healing efficiency of 95% after 6 h at 65 °C. Also, by adding reversible gold-thiolate bonding as a healing motif under near-infrared laser, the damaged ionogels self-heal within 10 min to have a high healing efficiency (&gt;80%). The fabricated supercapacitor based on PGB ionogel electrolyte also shows a high air stability for 14 days under ambient air conditions and high capacitance retention after 5000 galvanostatic charge-discharge cycles. Our synthesized PGB ionogel electrolyte can widen the voltage window of the supercapacitor (&gt;1.0 V), higher than that of hydrogel electrolyte. Furthermore, a self-healing strain sensor with a gauge factor of 0.8 to detect bio-signals is fabricated using the PGB ionogel due to its intrinsic ionic conductivity. This work suggests a high application potential of our synthesized ionogel in energy storage devices and bio-signal monitoring sensors with longevity for wearable electronics.