Structural, Microstructural and Electrochemical Properties of Dispersed Type Polymer Nanocomposite Films

Abstract

The free standing solid polymer nanocomposite films has been prepared through standard solution cast technique. The improvement in structural, microstructural and electrochemical properties has been observed on the dispersion of nanofiller in polymer salt complex. X Ray diffraction studies clearly reflect the formation of complex formation as no corresponding salt peak appeared in the diffractograms. The FTIR analysis suggested a clear and convincing evidence of polymer ion, ion ion and polymer ion nanofiller interaction. The highest ionic conductivity of the prepared solid polymer electrolyte films is 5x10-5 S cm-1 for 7 wt. TiO2. The Linear Sweep Voltammetry provide the electrochemical stability window of the prepared solid polymer electrolyte films, which is of the order of 3.5 V. The ion transference number has been estimated, tion is 0.99 through dc polarization technique. Dielectric spectroscopic studies were performed to understand the ion transport process in polymer electrolytes. All solid polymer electrolyte possesses good thermal stability up to 300C. DSC analysis confirms the decrease of melting temperature and signal of glass transition temperature with addition of nanofiller which indicates the decrease of crystallinity of polymer matrix. An absolute correlation between diffusion coefficient, ion mobility, number density, double layer capacitance, glass transition temperature, melting temperature, free ion area and conductivity has been observed. A convincing model to study the role of nanofiller in polymer salt complex has been proposed which supports the experimental findings. The prepared polymer electrolyte system with significant ionic conductivity, high ionic transference number, good thermal, voltage stability could be suggested as a potential candidate as electrolyte cum separator for fabrication of rechargeable lithium-ion battery system.