Ion transport property of hot-press cast Mg²⁺-ion conducting nano-composite polymer electrolyte membranes: Study of effect of active/passive filler particle dispersal on conductivity

Abstract

Ion transport properties of Mg²⁺-ion conducting nano composite polymer electrolyte (NCPE) films have been investigated. NCPE membranes were cast by a completely dry/solution free hot-press technique. Solid Polymer Electrolyte (SPE) composition: [85PEO: 15Mg(ClO₄)₂], identified as the highest conducting film in a separate study with room temperature conductivity σ ~ 2.27<img src='/image/spc_char/cross.gif' border=0>10^{-6 </span>}S /cm, has been used as I^st-phase host matrix and different active (<span style="mso-ansi-language:EN-IN; mso-fareast-language:EN-IN">micro/nano-sized MgO) and passive (<span style="mso-ansi-language:EN-IN;mso-fareast-language:EN-IN">nano-sized SiO₂ and <span style="mso-ansi-language: EN-IN;mso-fareast-language:EN-IN">TiO₂) filler particles as II^nd-phase dispersoid. Effect of fillers of different nature on ionic conductivity has been studied. As a consequence of dispersal of filler particles in fractional amount, conductivity (σ) enhancement of approximately one order of magnitude could be achieved at room temperature along with substantial improvement in the mechanical integrity of the film. The total ionic transference number (<i style="mso-bidi-font-style: normal">t</i>_ion) and the cationic (Mg²⁺) transference number (<i style="mso-bidi-font-style:normal">t</i>₊) have been determined using <i style="mso-bidi-font-style:normal">dc </i>polarization and a combined <i style="mso-bidi-font-style:normal">ac/dc</i> IS techniques, respectively. Active filler particles resulted in the considerable increase in <i style="mso-bidi-font-style:normal">t</i>₊ of NCPE film. The activation energy (<i style="mso-bidi-font-style:normal">E</i>_a) has also been computed from temperature dependent conductivity plot.

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