Structural and electrochemical properties of Nichrome anode thin films for lithium battery

Abstract

Low cost anode materials having a high electrochemical efficiency have been critical in the success of thin film batteries that are applicable in ubiquitous environments as a portable energy source. Nichrome thin films are ideally suited for use in hybrid assemblies but their applications include precision integrated circuits in fields of telecommunications, instrumentation, power supplies, military and medical equipment where low noise and good power dissipation are required. With such a wide spectrum of applications, it is important to understand the electric behavior of the Nichrome alloy thin films by their microstructure. In this work, nanocrystalline films of nickel chromium alloys were deposited on alumina substrate by radio frequency (RF) magnetron sputtering technology. High purity nickel and chromium sputtering target were used for the deposition. First, aluminum was deposited on ceramic substrate acts as a current collector and over that NiCr was deposited by RF sputtering method. Both the layers were analyzed for structural and electrical properties using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDS), atomic force microscopy (AFM), scanning electron microscopy (SEM) and cyclic voltammetry. The XRD peak confirms that deposited NiCr and Aluminum have tetragonal and cubic structures, respectively. The crystallite size was determined by full width at half maximum of XRD peaks. Structure, composition and the properties of the film are the major focus of this paper. Composition ratio between nickel and chrome obtained by EDS is 1:1. Particle size and microstructure of the film have been studied by SEM and AFM. Electrochemical properties of the films were analyzed. Reaction mechanism for the insertion and excretion is reported. After Lithium insertion and extraction the effect on the surface and structure of the thin film has been studied. The composition of equilibrium phases of NiCr as useful as attracting anode for the thin film battery. Nichrome on aluminum thin films as an anode has been attracted because it provides practical advantages including low cost production and competitive electrical performance.