Chitosan-assisted synthesis of wearable textile electrodes for high-performance electrochemical energy storage

Abstract

Through a facile “dipping and drying” process, reduced graphene oxide, here simply referred to as “graphene”, was successfully coated onto a commercial textile substrate, resulting in a high-performance supercapacitor electrode with excellent flexibility and stretchability. With the assistance of difunctional chitosan (for dispersing and gluing), a high graphene loading amount of 5.5 mg cm⁻² was achieved on cotton textile within 10 soaking times. The graphene@cotton-10 had a low sheet resistance of 1.75 Ohm sq⁻¹, which merely increased 0.51 and 0.78 Ohm sq⁻¹ when being bent at 180° and stretched with 100% strain, respectively. In a three-electrode configuration, the areal specific capacitance of the graphene@cotton-10 reached up to 232 mF cm⁻² at the current density of 1 mA cm⁻², which was superior to most of the carbon@textile flexible electrodes reported so far. The resulting graphene@cotton-10 symmetrical supercapacitor had a decent energy density of 4.38 μWh cm⁻² at 5 mW cm⁻². Cycling test revealed the supercapacitor had more than 80% retention of its initial capacitance after 5000 cycles at 5 mA cm⁻², demonstrating an outstanding long-term durability. Furthermore, the synthesis methodology established in this study is simple, efficient and environment-friendly, which possesses a great potential for large-scale practical applications.