High performance of asymmetric coin cells designed using optimized weight percentage of multiwalled carbon nanotubes in Ni/Co-MOFs nanocomposites

Abstract

• 20% of F-MWCNTs in Ni/Co-MOF was better than other weight % of F-MWCNTs. • Ni/Co-MOF/20% F-MWCNTs exhibited a high Cs of 1779 F/g at 2 mV/s & 890 F/g at 2.5 A/g. • The coin cell with Ni/Co-MOF/20% F-MWCNTs//AC offered ED-56 Wh/kg & PD-11 kW/kg. • Six-coin cells in series were used to power three red coloured LEDs for 3 minutes. Nanocomposites (NC-X) of Ni/Co-MOFs with varying weight % of functionalized multiwalled carbon nanotubes (F-MWCNTs) were synthesized by solvothermal method. Physicochemical properties of NC-X were analyzed by different analytical techniques. Further, electrochemical studies were made to comprehend the effect of weight % of F-MWCNTs in the nanocomposites for high-performance supercapacitors. 20 weight % of F-MWCNTs in the nanocomposite exhibited higher supercapacitance performance (890 F/g at 2.5 A/g) than other nanocomposites. The fabricated asymmetric coin cell (ASC) offered high energy and power densities of 56.25 Wh/kg and 11.9 kW/kg respectively with 20,000 cycle stability at 25 A/g (1 M KOH). The ASC also retained 72% capacitance with 100% coulombic efficiency at 20,000 th cycle. Six ASC of each cell with operating potential window of 1.8 V were utilized in powering three red light emitting diodes (LEDs-12 V) connected in series. Thus, demonstrating the practical application of ASCs to power LEDs for 3 minutes.