Ag+-ion conducting Nano-Composite Polymer Electrolytes (NCPEs): Synthesis, characterization and all-solid-battery studies

Ag ⁺ -ion conducting Nano Composite Polymer Electrolyte (NCPE) films: [90PEO: 10AgCF ₃SO ₃] + xAl ₂O _3, where x = 0.5, 1, 1.5, 2, 3, 4, 5 wt.(%), have been prepared by a completely dry hot-press technique in place of the traditional solution-cast method. NCPE film, basically a two-phase organic composite polymer electrolyte, has been synthesized using Solid Polymer Electrolyte (SPE) composition: [90PEO: 10AgCF ₃SO ₃ ], identified as one of the high conducting films with room temperature (300 K) ionic conductivity (σ _rt) ~ 7.12 × 10 ^{− 7} S/cm and having superior mechanical flexibility, as 1st-phase host and nano-particles (size < 50 nm) of an insulating/inert filler material Al ₂O ₃ as 2nd-phase dispersoid. Filler particle concentration dependent conductivity measurements revealed NCPE film: [(90PEO: 10AgCF ₃SO ₃) + 3Al ₂O ₃] as Optimum Conducting Composition (OCC) with σ _rt ~ 2.57 × 10 ^{− 6} S/cm. A conductivity enhancement of more than 3-fold could be achieved in SPE as a consequence of dispersal of Al ₂O ₃ nano-particles. Also, NCPE OCC film physically appeared relatively more stable/flexible as compared to SPE host film. The characterization of ion transport properties in SPE host and NCPE OCC films has been done in terms of ionic conductivity (σ) and total ionic (t _ion)/cation (t ₊ ) transference numbers. These ionic parameters have been evaluated experimentally using different ac/dc techniques. The temperature dependent conductivity has also been studied and the activation energy (E _a) was computed by liner least square fitting of Arrhenius plot. The material characterization was done by analyzing X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) responses on the film samples. All-Solid-State batteries in the cell configuration Ag (anode)//NCPE OCC film//(I ₂ + C + NCPE) (cathode) have been fabricated and the cell-potential discharge performances have been studied under varying load conditions. An Open Circuit Voltage (OCV) ~ 0.56 V was obtained. Some important cell parameters have been evaluated from the cell potential discharge profiles. The battery performed quite satisfactorily especially under low current drain states.