Electrochemical Deposition and Characterization of Ni-Fe composite Nanowires As Supercapacitor Anode

Abstract

With increasing energy demands in hybrid vehicles and portable electronics, the scientific community and society shows more interest towards the development of the technologies capable of storing large amount of energy [1,2]. Researchers, all around the world are working hard for the development of energy storage devices such as capacitors, batteries, supercapacitors etc [3-5]. Supercapacitor devices are safe and promising alternative energy storage devices as compared to batteries [6]. Among the supercapacitors, pseudocapacitors due to their high performance and low cost are favored choice with the possibility of commercialization. Also for high performance supercapacitor, the selectivity and morphology of the electrode material plays key role. As a result, various transition metals, their oxides as well as composites with different morphologies are explored as electrode materials. Among these, metal ferrites demonstrate high potential in energy storage applications as well as nickel, due to its high conductivity gains great interest in this field. In this work, the electrochemically deposited Ni-Fe composite nanowires were investigated as supercapacitor anode in 6M KOH solution. The electrodeposition is performed in a three electrode electrochemical cell using a flexible conductive copper tape as substrate into a polycarbonate membrane. The electrodeposition is achieved cathodically in an electrolyte consisting of 10mM Iron nitrate nonahydrate (Fe(NO3)3.9H2O) and 40mM Nickel nitrate hexahydrate (Ni(NO3)2.6H2O) in 50ml DI water, with 99.99% platinum (Pt) wire as counter, silver/ silver chloride (Ag/AgCl with saturated KCl) as the reference electrode and the electrolyte as working electrode at -1.4 V at room temperature for 20 minutes. Then the synthesized Ni-Fe composite nanowires were allowed to dry at room temperature and after that dichloromethane (CH2Cl2) is used for releasing nanowires from polycarbonate membrane as dichloromethane will dissolve the polycarbonate membrane leaving behind only the vertical nanowires. Further, SEM, EDX, CV, GCD etc characterizations were performed to investigate the structure, morphology and electrochemical properties of the synthesized nanowires for energy storage application.