Smart dual-functional energy storage/fluorescent textile device based on a new redox-active Mn-doped ZnS solid-gel electrolyte

Abstract The evolution of wearable technologies boosted the development of energy storage textiles that can be charged faster and store energy for longer time. Achieving multifunctionality on textiles is a key milestone towards higher value-added smart products. Herein, we report on the fabrication of a novel dual-functional textile device merging enhanced energy storage performance with optical properties. A redox-active solid-gel electrolyte based on fluorescent manganese(II)-doped zinc(II) sulfide was for the first time used to endow the dual functionality to the device when combined with MWCNT-coated textile electrodes. The textile electrodes were prepared through an eco-sustainable straightforward dip-pad-dry process using a natural cotton fabric substrate. The fluorescent hybrid textile supercapacitor exhibited enhanced energy storage performance relative to the EDLC-type analogue containing the undoped electrolyte, namely 20% higher working voltage (1.64 V), 48% higher energy density (1.63 W h kg−1) and 74% higher power density (641.6 W kg−1). Additionally, it presented excellent cycling stability (100%) after 8000 charge/discharge cycles. The device exhibited intense yellow-orange fluorescence under UV light, while preserving the energy storage functionality. This work demonstrated the versatility of this type of devices for dark environment applications, namely in reflective/safety electronic clothing for nighttime users.