Highly Stretchable, Elastic, Healable, and Ultra-Durable Polyvinyl Alcohol-Based Ionic Conductors Capable of Safe Disposal

Abstract

Open AccessCCS ChemistryRESEARCH ARTICLE5 Sep 2022Highly Stretchable, Elastic, Healable, and Ultra-Durable Polyvinyl Alcohol-Based Ionic Conductors Capable of Safe Disposal Siheng Li, Yixuan Li, Yuting Wang, Hongyu Pan and Junqi Sun Siheng Li State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 , Yixuan Li State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 , Yuting Wang State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 , Hongyu Pan State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 and Junqi Sun *Corresponding author: E-mail Address: [email protected] State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 https://doi.org/10.31635/ccschem.021.202101360 SectionsSupplemental MaterialAboutAbstractPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Highly durable and stretchable ionic conductors are indispensable components of flexible electronics. However, fabricating such ionic conductors that are also non-toxic and biodegradable remains a challenge. In this study, highly stretchable, elastic, healable, and ultra-durable ionic conductors capable of non-hazardous disposal are conveniently fabricated by complexation of vanillin-grafted polyvinyl alcohol (VPVA) and ionic liquids (ILs) (denoted as VPVA-IL). No leakage of the loaded ILs occurs after repeatedly heating and pressing the ionic conductors. The VPVA-IL ionic conductor has an ionic conductivity of ∼0.67 S m−1, a tensile strength of ∼2.01 MPa, and a strain at break of ∼1231%. Meanwhile, the VPVA-IL ionic conductor shows a highly reproducible electrical response during 1100 uninterrupted extension-release cycles at a strain of 400%, demonstrating its excellent fatigue resistance and durability. Because of the reversibility of hydrogen bonds, the fractured ionic conductors can be easily healed at ∼70 °C, restoring their original conductivity, stretchability, elasticity, and durability. Highly pure ILs can be easily separated from the VPVA-IL ionic conductors for reconstruction into new ionic conductors. The VPVA matrices, which are capable of completely degrading into non-toxic substances in soil, can be safely discarded without polluting the environment. Download figure Download PowerPoint Introduction Flexible electronics have experienced a development boom over the past decade, bringing about large changes in society.1–5 Stretchable ionic conductors play an important role in various flexible electronics and are widely used in flexible batteries, soft robots, and flexible sensors.4–9 With the pursuit of superb flexible electronics to better serve users, there is increasing demand for stretchable ionic conductors with high stretchability, outstanding elasticity, and satisfactory ionic conductivity even in highly stretched states.9–12 However, large deformations can cause fatigue and mechanical damage of stretchable ionic conductors in practical applications, severely reducing their reliability and shortening their service life. Therefore, stretchable ionic conductors need to simultaneously possess excellent fatigue resistance and self-healing properties to improve their durability for long-term service.13–15 Healing of ionic conductors can be realized through the reversibility of non-covalent interactions of polymer chains containing ionic liquids (ILs), deep eutectic solvents, and electrolyte salts.14–19 Although various stretchable ionic conductors have been fabricated, these conductors still need better elasticity, fatigue resistance, and durability, especially under uninterrupted large deformations (>200%) (see Supporting Information Table S1).11–14,18–32 Until now, the most durable ionic con