Synthesis and investigation of electrochemical behavior of Ni-Co compounds in order to use as electrochemical supercapacitor

Nowadays because the increasing of energy resources and the reduction of fossil fuel resources, researches are focused on clean and renewable energy sources such as batteries, fuel cells and supercapacitors [1,2]. Supercapacitors are electrochemical capacitors that have very high capacities. The energy density of supercapacitors, on average, 10 to 100 times are more than batteries [3]. various groups are studying on supercapacitors to discover cheap and high capacitance supercapacitors. In this project first layered double hydroxide compound of Ni-Co was electrochemically synthesized and then was heated to convert oxide form. XRD, EDX and SEM methods was used to confirming of mentioned compound. Then various parameters that can affect the synthesis of was investigated like: The ratio of Co/Ni concentration, applied potential for synthesis of LDH, oxidation time and temperature, concentration of electrolyte. Optimized conditions for synthesis are: Co/Ni: 2/1, applied potential: -1.1 vs. AgCl/Ag, precipitation time: 500 s, oxidation time and temperature are 1h and 100°C respectively and electrolyte concentration: 6M. In the next step the behavior of synthesized compound was investigated as supercapacitor. In order to investigation, Cyclic voltammetry (CV), Electrochemical Impedance Spectrometry (EIS) and Charge-Discharge cycles (CD) methods was used. Finally, 1510.49 F/g, 41.18 Wh/kg and 124.22 W/kg was obtained for specific capacitance (ʋ=5 mV/s), specific energy and specific power (di=1A/g).