Nanocomposites and nanomaterials

Hydrothermal synthesis of nanocrystal NiMoO4 for hybrid capacitors application
Popovych O.V., Budzulyak I.M., Popovych O.M., Kotsyubynsky V.O. 
Vasyl Stefanyk Precarpathian National University, 57 Shevchenko St. Ivano-Frankivsk-76018, Ukraine. 
E-mail: khemiiolha@gmail.com 

Nanostructured materials deserve much of attention due to their unique electrochemical, optical, magnetic, electrical and photocatalytic properties [1]. Among them nickel molybdate (NiMoO4) is a promising electrode material due to its higher total capacity and higher electro conductivity. Nanocrystal nickel molybdate was obtained by hydrothermal method. With this purpose 10 mmol of Ni(NO3)2·6H2O and 10 mmol of Na2MoO4·2H2O were being dissolved in 40 ml of distilled water until transparent solution was obtained. The solution was kept in an autoclave at 180 ℃ during 2 hours. The autoclave was cooled down to ambient temperature; the given residue was flushed several times with distilled water and dried in the furnace in the atmosphere at the temperature of 70 ℃. 

Fig.1. Galvanostatic charge / discharge curves of hybrid capacitor NiMoO4 / carbon material

We have formed hybrid two-electrode cell to determine the practical application of electrode based on nickel molybdate. The obtained nickel molybdate was used as cathode and carbon material was used as the anode. The nonlinearity of the galvanostatic charge / discharge curves (Fig.1) confirms the pseudocapacitive behavior of the cathode material caused by electrochemical adsorption and redox reactions at the electrode / electrolyte interface. The specific capacitance of hybrid capacitor based on NiMoO4/carbon material was 256, 215 and 176 F/g at currents of 0.2, 0.5 and 1 A/g respectively. 

1.	Khemii O., Budzuliak I., Kotsyubynsky V., Yablon L., Ilnytskyi R., Boychuk V., Morushko O., Bandura K., Khemii M. Materials Science-Poland.- 2019.-37, N 4.-P.547.