Asymmetric supercapacitor with Mn-Ni-Co vanadate and carbon black incorporated FeMoO4 electrodes

An asymmetric supercapacitor with tri-metallic (Mn, Ni, Co) vanadate and carbon black-incorporated iron molybdate is fabricated and studied for supercapacitor applications. Mn0.33Ni0.33Co0.33V2O6 (MNCVO) is used as positive electrode and FeMoO4 + 40 wt% carbon black porous nanocomposite (FeMO_PNG_40CB) as negative electrode. Ni imparts a net-like morphology in MNCVO for effective ion accommodation. The electrochemical characteristics and performance of the individual electrode materials and the device (MNCVO||KOH||FMOC) are studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge (GCD). The discernible redox peaks in CVs of MNCVO in 1 M KOH indicate battery-like Faradaic charge storage. MNCVO exhibited specific capacitance (Csp) of ∼733 F g−1 at 1 A g−1. FeMo_PNG_40CB displayed Csp ∼ 634 F g−1 at 1 A g−1 in ∼0.90 V vs SCE potential window. The fabricated asymmetric supercapacitor with the above-mentioned electrodes delivered ∼121 F g−1 (∼54 mAh g−1) at 1 A g−1. The energy and power densities of this device are ∼43 Wh kg−1 and ∼ 790 W kg−1, respectively, at 1 A g−1. These values are ∼33 Wh kg−1 and ∼ 8411 W kg−1, respectively, at 10 A g−1. The device exhibited good cycling stability with ∼87 % capacitance retention after 6000 galvanostatic charge-discharge cycles at an operating voltage of ∼1.60 V.