Development of NiS@f-MWCNT nanocomposite-based high-performance supercapacitor coin cell prototype device

This work reports the fabrication of supercapacitor coin cell prototype devices using lab-made NiS@f-MWCNT, their in-depth physical and electrochemical characterization, and the design of Arduino-based set-up to power temperature sensor. A one-step hydrothermal technique was developed to rationally synthesize bare NiS and f-MWCNT decorated NiS nanocomposites (NiS@f-MWCNT) using CTAB as a surfactant. Loading of f-MWCNT into NiS resulted in an enhancement in electrochemical characteristics. The specific capacitance values are found to be 1400 Fg−1 and 1966 Fg−1 (at 1 Ag−1) for bare NiS and NiS@f-MWCNT, respectively. Further, an improvement in rate capability is also noticed in the case of the f-MWCNT loaded sample (78.0 %) vis-à-vis bare NiS (64.0 %). The as-prepared NiS and NiS@f-MWCNT were utilized as the positive electrode while activated carbon (AC) as a negative electrode to fabricate distinct asymmetric supercapacitor coin cells, namely NiS//AC and NiS@f-MWCNT//AC, respectively. The as-fabricated NiS@f-MWCNT//AC supercapacitors exhibited a high energy density of ∼74.1 Whkg−1 (vis-à-vis 58.0 Whkg−1 for NiS//AC) and power density of 1405.0 Wkg−1 (vis-à-vis 850.0 Wkg−1 for NiS//AC), respectively. In addition, four ASCs composed of NiS@f-MWCNT//AC were used in demonstrating the hands-on process for powering an Arduino-driven temperature sensor. The as-developed set-up was sensitive enough to record a minor temperature fluctuation with an accuracy of ±1 °C.