A robust, biodegradable and recyclable all-cellulose ionogel from low-value wood

Abstract

For thousands of years, wood has been utilized as a natural, abundant, and sustainable material for structural construction and furniture. To enhance its value, we have developed a simple process that can directly convert low-value wood (including cracked wood, chips, shives, and other wood residues) into high-performance all-cellulose ionogels. This process involves delignification, in situ dissolution of cellulose, and self-assembly of molecular cellulose chains. The resulting ionogel exhibits excellent properties such as high ion conductivity (∼60 mS/cm), mechanical strength (∼6 MPa), and self-healing capability (∼10 min). Notably, it also demonstrates exceptional freeze tolerance, withstanding temperatures as low as −50 °C while maintaining high ion conductivity (∼6.4 mS/cm). The ionogel is a versatile substrate for flexible electronic circuits. We have developed a sensor utilizing this ionogel that is breathable, flexible, and highly responsive to temperature, humidity, and strain. Furthermore, we have used it as a gel electrolyte to create supercapacitors with exceptional performance even in low-temperature conditions. The ionic liquid can be reused, with an all-cellulose framework that breaks down naturally in moist soil within 15 days. This sustainable method of producing high-performance ionogels from low-value wood has immense potential in shaping the next generation of soft, intelligent devices.