O. Padmaraj, E.S. Srinadhu, N. Satyanarayana
Keywords: nanocomposite, polymer blend electrolyte, electrospinning, charge/discharge
Summary:Rechargeable lithium batteries are considered as the best power source for fast growing portable electronic devices, automotive electric vehicles, aerospace, etc., applications. Based on applications, the researchers are focusing on the development of various properties materials for lithium batteries with good electrochemical performance, like high energy density, long cycles life, safety, reliability, etc. Solid polymer electrolytes (SPEs) have been used as a separator-cum-electrolyte, in place of liquid electrolytes, due to their unique properties such as flexibility, light weight, electrolyte leak proof construction, desired size & shape, miniaturization, high thermal, good chemical & electrochemical stability, etc. Despite of several advantages, SPEs possess some drawbacks such as low ionic conductivity at room temperature, poor interfacial stability between the electrodes, etc. In order to improve their ionic conductivity, physical and electrochemical properties at room temperature, several approaches have been tried to modify the polymer host matrix with plasticizer, polymers blend and ceramic fillers (TiO2, Al2O3, SiO2, MgO, ZnO, etc.) to form blended composite polymer electrolyte membrane for obtaining improved properties. Hence, the present work deals the development of electrospun hybrid nanocomposite PMMA blend fibrous electrolyte membranes with various x wt.% of ZnAl2O4, (x = 2, 4, 6 and 8) ceramic fillers by an electrospinning technique. Figs.1 & 2, respectively show the X-ray diffraction and scanning electron microscopy results of the prepared nanocomposite PMMA blend [90% P(VdF-co-HFP)/10% PMMA/x wt.% ZnAl2O4, (x = 2, 4, 6 and 8)] fibrous membranes. The activated separator-cum nanocomposite PMMA blend fibrous electrolyte membranes were obtained by soaking in an organic liquid electrolyte solution containing 1 M LiPF6 in EC: DEC (1:1, v/v). The newly developed novel nanocomposite PMMA blend fibrous electrolyte membranes showed low crystallinity, high thermal stability, low average fiber diameter, high electrolyte uptake, high conductivity (4.135×10-3 Scm-1) and good potential stability above 4.5 V at room temperature. Fig.3, shows the charge/discharge capacity and cycling performance of the fabricated CR 2032 (Li/NCPBEs/LiCoO2) lithium cell, using the newly developed nanocomposite polymer blend electrolyte membrane and the cell delivers an initial discharge capacity of 157 mAh g-1 and also exhibits stable cycle performance at current density of 0.1 C - rate at room temperature. Detailed results will be presented and discussed.