SYNTHESIS AND CHARACTERIZATION OF NANOSTRUCTURED METAL NITRIDE ELECTRODES FOR ENERGY STORAGE APPLICATIONS

Abstract

Developing new materials with high performance is essential to obtain efficient electrochemical energy storage devices. The excellent properties of nano-materials provide unique opportunities to achieve highly efficient electrochemical energy storage devices such as Li-ion batteries, supercapacitors, and fuel cells. The physical properties, such as a large surface area and novel size effects of nanostructured materials, highly improve the efficiency of such electrochemical energy storage devices. Nanostructured materials are becoming essential in developing electrochemical storage devices. In recent years, enormous research has been done to design and develop energy storage devices based on nanostructure materials, including supercapacitors, batteries, and fuel cells, to fulfill the energy requirement for current and next-generation. Among all these energy storage devices, the electrochemical supercapacitor is considered an intermediate between batteries and conventional capacitors due to its long life span, high power density, and good charging/discharging characteristics. Supercapacitors are of two types; the first is known as electric double-layer capacitors (EDLC), which store charge by adsorbing electrons onto the electrolyte-electrode double layer, whereas the second is pseudo-capacitors store the charge by faradic and non-faradaic mechanisms. Like the battery, a complete supercapacitor device has four main parts: cathode (positive electrode), anode (negative electrode), electrolyte, and separator. Among four, active electrodes finalize the performance and cost of the SCs, and nanostructured functional materials proved to be a worthy choice. In the current scenario, transition metal oxide, carbides, nitrides, and phosphides-based electrodes have gotten enormous attention due to their unique physio-chemical properties such as hardness, chemical durability, high conductivity, wear, and corrosion resistance. These properties make them encouraging and promising electrode materials for application purposes in SCs. The main problem in most oxide-active materials is their relatively low electrical conductivity, obstructing their performance rate. Non-oxide functional materials with ultra-hydrophilicity and high conductivity, including sulfides and carbides, have a significant drawback because their maximum sweep rate is limited to 1 Vs−1. Metal nitrides, such as titanium nitride (TiN), demonstrate excellent hardness, higher conductivity, and stability than their respective carbides (TiC) and offer high-energy storage.