Ecoflex-assisted quasi-solid-state flexible hybrid supercapacitors based on binder-free nanoflower-like CoxMo3-xS3 and Te-infused radish-derived bio-carbon for sensing and healthcare applications
Edugulla Girija Shankar, Mandar Vasant Paranjape, Jae Su Yu
Abstract
Advancements in electronic devices have driven the fabrication of flexible supercapacitors (SCs) to power electronic devices in twisted or bent states. In this regard, we report the fabrication of nanoflower-like arrays of cobalt molybdenum sulfide (Co x Mo 3-x S 3 ) on flexible and conductive carbon cloth via a facile single-step electrodeposition technique as a positive electrode. The morphological, physiochemical, and electrochemical characteristics of the corresponding electrodes are evaluated. For optimization, the Co x Mo 3-x S 3 electrodes with various stoichiometric ratios of Co/Mo in the precursor solution are fabricated. The optimized Co x Mo 3-x S electrode shows a maximum areal capacitance value of 1008.7 mF cm −2 at 2 mA cm −2 and an excellent life duration with areal capacitance retention value of ~ 100% over 10,000 galvanostatic charge–discharge (GCD) cycles. Furthermore, Te-infused carbon derived from radish is explored as a green negative electrode. A flexible hybrid SC (FHSC) device is fabricated using optimized Co x Mo 3-x S 3 and Te-infused radish-derived bio-carbon as the positive and negative electrodes, respectively. The corresponding FHSC device exhibits excellent electrochemical properties with power and energy density values of 7500 W kg −1 and 19.2 Wh kg −1 , respectively, followed by outstanding long-term durability with a specific capacitance retention value of ~ 100% over 10,000 GCD cycles. Finally, the FHSC device successfully powers various electronic gadgets in contorted states, thereby demonstrating its practical feasibility. The ecoflex-packaged FHSC device is also employed to power temperature and humidity sensors in the wearable condition for wireless internet of things applications.