Synergetic effect of ternary MnVMo-oxide electrode by hydrothermal method for high-performance asymmetric supercapacitor
Aviraj M. Teli, Sonali A. Beknalkar, Sagar M. Mane, Manesh A. Yewale, Tukaram D. Dongale, Jae Cheol Shin
Abstract
The binder-free deposition facilitates fast electron transfer and smoothens the diffusion path of electrolyte ions into the matrix of electrode material. Herein, the ternary metal oxides , such as manganese vanadium molybdenum oxide (MnVMo-oxide) is directly deposited on nickel foam by a single-step hydrothermal method . X-ray diffraction study confirms formation of MnVMo-oxide phase. The X-ray photoelectron spectroscopy confirms the Mn, V, and Mo are in the +2 (and +3), +5, and +6 oxidation states. Deposition time variation results, change in nanostructures from nanoparticle-assembled sheets to rectangular nanosheets , also the size of micro rods. The porous microrods formed with uneven quasi-rectangular shaped nanosheets of MnVMo-oxide exhibit high areal capacitance of 814.5 mFcm −2 (as compared to other electrodes) measured in 1 M KOH electrolyte at 3 mAcm −2 current density. The enhanced capacitance of the MnVMo-8 electrode is due to the dominance of the diffusion process over the capacitive-controlled contribution and high diffusion coefficient . The fabricated asymmetric supercapacitor device MnVMo-oxide//activated carbon shows good areal capacitance of 40 mFcm −2 with 0.025 mWhcm −2 energy at 1.5 mWcm −2 power density measured at 2 mAcm −2 current density, and cyclic stability of about 71.45 % (Coulombic efficiency of 98 %) quantified up to ∼9000 consecutive cycles.