SYNTHESIS AND CHARACTERIZATION OF METAL OXIDE THIN FILMS FOR SUPERCAPACITOR APPLICATION

Abstract

In recent years, enormous research has been done to design and develop energy storage devices which include supercapacitors, batteries and fuel cells, etc to fulfill the requirement of energy for current and next-generation. Among all these energy storage devices, the electrochemical supercapacitor is taken into account as an intermediate between batteries and conventional capacitors due to its long-life span, high power density, and good charging/discharging characteristics which can fulfill the energy and power gap between batteries, and conventional capacitor. Supercapacitors are of two types i.e., the first one is known as electric double-layer capacitors (EDLC) which store the charge by faradic and non-faradic mechanisms whereas the second one is pseudo-capacitors which store the charge by adsorbing electrons onto the electrolyte-electrode double layer. Metal oxide materials show enhanced electrochemical performance in terms of Pulse, and chemical properties as compared to their metal counterparts. Over the last few decades, different thin film-based metal oxides cobalt oxide (Co3O4), Molybdenum oxide (MoO2), chromium oxide (Cr2O3), tin oxide (SnO2), titanium oxide (TiO2), zinc oxide (ZnO) and cerium oxide (CeO2) materials have been extensively investigated by the researchers due to several applications such as the battery, gas sensing, photocatalysis, supercapacitor, solar cell, and fuel cell. Based on metal oxide materials, the pseudo-capacitance mechanism has the advantage due to its high capacitance, which accesses a higher amount of energy density in comparison to EDLC. This is the reason that all transition metal oxide electrodes can be investigated as pseudo-capacitor. Moreover, another reason to raise the importance of the metal oxide-based thin film is its high capacitance, high conductivity, good transparency, and large surface area which provide more active sites for the redox reaction process.