Ion transport and electrochemical cell performance studies on hot-press-synthesized Ag⁺ion conducting electroactive polymeric membranes: (1 −x)PEO:x[0.7(0.75AgI : 0.25AgCl) : 0.3MI]

Abstract

Investigations on ion transport properties of new Ag+ ion conducting electroactive solid polymer electrolyte (SPE) membranes (1 − x)PEO: x[0.7(0.75AgI : 0.25AgCl): 0.3MI] (M ≡ Rb, K), where x = 0 < x < 50 wt (%), are reported. A novel hot-press/solvent-free dry technique has been used for complexing/dissolving the salts into the PEO polymeric host. The two complexing salts [0.7(0.75AgI : 0.25AgCl): 0.3MI], recently investigated at the present laboratory, are the solid-solution-synthesized quaternary superionic solids in the polycrystalline phase which exhibited Ag+ ion conductivity σ ∼ 10−3 S cm−1 at room temperature. The compositional (x) dependent conductivity (σ) studies identified the composition 70PEO : 30[0.7(0.75AgI : 0.25AgCl) : 0.3MI] as the optimum conducting composition (OCC) SPE films. σ-enhancement of approximately three orders of magnitude could be achieved in both OCC SPEs at room temperature from that of the pure polymeric host: PEO. To explain the σ-increase in OCC SPE films, ionic mobility (μ) has been determined experimentally at room temperature using the d.c. polarization transient ionic current (TIC) technique and, subsequently, the mobile ion concentration (n) has been evaluated from σ and μ data. The ionic transference number (tion) in OCC SPEs has been estimated from the TIC ‘current–time’ plot and, hence, the ionic drift velocity (vd) has been evaluated. The phase identification and material characterization studies on both OCC SPEs have been done by XRD, SEM and DTA techniques. The temperature dependent studies on the ionic parameters, namely σ, μ, n, tion, vd, provided a deeper insight to understand the ion conduction phenomenon in OCC SPEs along with the information regarding energies involved in different thermally activated processes. Thin film SPE batteries have been fabricated using the two OCCs: 70PEO: 30[0.7(0.75AgI : 0.25AgCl): 0.3RbI]; 70PEO: 30[0.7(0.75AgI : 0.25AgCl): 0.3KI] as electrolytes, sandwiched between the Ag-metal foil anode and the hot-pressed cathode film: (C + I2 + SPE) in 1 : 1 : 1 wt (%). The cell potential discharge performances have been studied at room temperature under varying load conditions.

Ionic drift velocity measurement on hot-pressed Ag+ ion conducting glass-polymer electrolytes

“…Also, the magnitude of peak current (I T ) increased as the sample got hot, as also observed in our earlier communications. 14,23,24 This may be attributed to the increase in n and/or ionic drift velocity (v d ).…”

Ionic Drift Velocity Measurements on A Nano-composite Polymer Electrolyte: 95[90PEO: 10AgNO[sub 3]]: 5SiO[sub 2]

“…In this d.c. polarization TIC measurements on ionic/ superionic systems, including polymer electrolytes, it has been always assumed that the initial total current I T , obtained in the 'current-time' TIC plots, would be directly proportional to the applied d.c. voltage (V) i.e. the Ohm's law would be valid and hence, the effect of polarization charge build-up would be negligible during the measurements [10,15]. 'I T vs V' plot for the OCC NCPE, as shown in Fig.…”

“…However, recently, an alternate hot-press technique has been developed for casting completely dry polymer electrolyte films. Hot-press technique shows several procedural advantageous over the traditional solution-cast method [7,10,11]. In the present paper, author reports the ionic drift velocity (v d ) measurements on a hot-press synthesized nano-composite polymer electrolyte (NCPE) membrane: 95 [90PEO: 10AgNO 3 ]: 5 SiO 2 at different temperatures.…”

Hot-pressed Ag+Ion Conducting Glass-Polymer Electrolytes: Synthesis and Battery Application

“…SPE/ NCPE/ GPE films are prepared, in general, by a traditional solution-cast method. However, recently a novel hotpress technique has been developed for casting SPE/ NCPE films [9][10][11][12][13]. In the present paper, we report the synthesis of a new Ag + ion conducting PEObased glass polymer electrolyte has been prepared using the melt-quenching technique [14].…”

“…It resulted into a soft lump/ slurry which was then pressed (~ 1.25 ton/ cm 2 ) between two SS-cold blocks, giving rise to a uniform film of thickness ~ 0.013 cm. The details related to hotpress casting of other SPEs/ NCPEs have been given elsewhere in the literature [10][11][12][13]. Material characterizations were done with the help of SEM (model: JEOL, JXA-8100, Japan) and DSC (model: Perkin Elmer) techniques.…”