Angesh Chandra

Ion transport property studies on PEO–PVP blended solid polymer electrolyte membranes

The ion transport property studies on Ag+ ion conducting PEO–PVP blended solid polymer electrolyte (SPE) membranes, (1 − x)[90PEO : 10AgNO3] : xPVP, where x = 0, 1, 2, 3, 5, 7, 10 (wt%), are reported. SPE films were caste using a novel hot-press technique instead of the traditional solution cast method. The conventional solid polymeric electrolyte (SPE) film, (90PEO : 10AgNO3), also prepared by the hot-press method and identified as the highest conducting composition at room temperature on the basis of PEO–AgNO3-salt concentration dependent conductivity studies, was used as the first-phase polymer electrolyte host into which PVP were dispersed as second-phase dispersoid. A two-fold conductivity enhancement from that of the PEO host could be achieved at room temperature for PVP blended SPE film composition: 98(90PEO : 10AgNO3) : 2PVP. This has been referred to as optimum conducting composition (OCC). The formation of SPE membranes and material characterizations were done with the help of the XRD and DSC techniques. The ion transport mechanism in this SPE OCC has been characterized with the help of basic ionic parameters, namely ionic conductivity (σ), ionic mobility (μ), mobile ion concentration (n) and ionic transference number (tion). Solid-state polymeric batteries were fabricated using OCC as electrolyte and the cell-potential discharge characteristics were studied under different load conditions.

Synthesis, characterization and ion transport properties of hot-pressed solid polymer electrolytes (1−x) PEO:x KI

Synthesis and ion transport properties of hot-pressed solid polymer electrolytes (SPEs), (1−x) PEO: x KI, where x is the content of KI in wt%, are reported. A hot-press technique has been used for the formation of the polymeric membranes in place of the usual solution cast method. The composition (80 PEO:20 KI) was identified as the highest conducting polymer electrolyte on the basis of compositional dependent conductivity studies of PEO:KI films. A conductivity enhancement of more than two orders of magnitude from that of the pure PEO was achieved. Materials characterization and ion transport mechanism were explained by using various experimental techniques.

Ionic Mobility, Drift Velocity, and Dielectric Studies on Ag + Ion Conducting Glassy Electrolytes

Ionic mobility (μ), ionic drift velocity (v_d), and dielectric measurements of new Ag^+ ion conducting glassy systems: x[0.75AgI: 0.25AgC1]: (1 - x)[Ag_2O: V_2O_5], where 0:1 ＜ x ＜ 1 in molar weight fraction, are reported. The present glassy electrolytes have been synthesized by the melt-quench technique using a high-speed twin roller-quencher. An alternate host salt: ’quenched [0.75AgI: 0.25AgC1] mixed system/solid solution’ has been used in place of the traditional host AgI. The compositional dependence conductivity studies on the glassy systems indicated that the composition 0.8[0.75AgI: 0.25AgC1]: 0.2[Ag_2O: V_2O_5] shows the highest conductivity (σ ~ 9.0 × 10^(-3) S/cm) at room temperature. Some other basic ion transport parameters, viz. the mobile ion concentration (n) and ion transference number (t_(ion)), have also been characterized using different experimental techniques.

Dielectric study of hot-pressed nanocomposite polymer electrolytes

Ion-conducting nanocomposite polymer electrolyte films based on poly(ethylene oxide)-NaPO3 3: 1 with up to 15 wt % of SiO2 have been prepared using recently developed hot-press technique instead of conventional solution cast method. With 7 wt % of SiO2, the film conductivity has been enhanced by an order of magnitude. The materials have been characterized by Fourier transform infrared spectrometry and thermogravimetric analysis. For the composition with the highest conductivity, the temperature dependences of ionic mobility, mobile ions concentration, ionic transference number, and ionic drift velocity have been determined. Dielectric constant and dielectric loss have been measured. The conductivity enhancement has been discussed on the basis of existing theories of dielectrics.

PEO-PVP blended Na+ ion conducting solid polymeric membranes

Polyethylene oxide (PEO)-polyvinylpyrrolidone (PVP) blended Na+ ion conducting solid polymeric membranes: (1−x) [75PEO:25NaPO3] + x PVP, where 0 < x < 12 wt%, are reported. The polymeric blending was done using a solventfree hot-press method. Two orders of conductivity enhancement (σ ca. 1.07 × 10−5 S·cm−1) have been achieved with 3 wt% of PVP (i.e. the composition: [97(75PEO:25NaPO3) + 3PVP]), from that of the pure host: (75PEO:25NaPO3). The conductivity enhancement in PEO-PVP blended solid polymeric membranes have been explained by the ionic conductivity, ionic mobility and mobile ion concentration measurements. Materials characterization and polymer-salt complexation were done with the help of X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) studies. The temperature dependent conductivity studies have also been done to compute the activation energy (Ea) values from lg σ1/T Arrhenius plots. A solid state polymeric battery was fabricated by using optimum conducting composition of solid polymer electrolyte (SPE OCC), and some important cell parameters were also calculated from the discharge profile of the cell.

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

Ionic drift velocity (vd) measurements of a new Ag+ ion conducting glass-polymer electrolytes (GPEs): (1−x) PEO : x [0.8(0.75AgI : 0.25AgCl) : 0.2(Ag 2O : V2O5)], where 0 < x < 50 wt%, were reported. GPEs were casted using the hot-press techniques developed in recent times. The composition: 70PEO : 30[0.8(0.75AgI : 0.25AgCl) : 0.2(Ag2O : V2O5)] with conductivity (σ) ∼ 7.7 × 10−7 S cm−1 was identified as highest conducting composition from the compositional-dependent conductivity studies. The ionic mobility (μ), mobile ion concentration (n), ionic transference number (tion) and ionic drift velocity (vd) of GPEs were determined at different temperatures with the help of the d.c. polarization technique and other well-known important relations.

Ionic Drift Velocity Measurements on A Nano‐composite Polymer Electrolyte: 95[90PEO: 10AgNO3]: 5SiO2

Ionic drift velocity (vd) measurements on a hot‐press synthesized nano‐composite polymer electrolyte (NCPE) membrane: 95[90PEO: 10AgNO3]: 5SiO2, are reported. The ionic transference number (tion) values were determined using dc polarization Transient Ionic Current (TIC) technique for vd measurement at different temperatures. The drift energy (Ed), involved in the thermally activated process was determined from the temperature dependent studies on ionic drift velocity using the log vd vs 1/T Arrhenius plot. At all the temperatures, the ionic drift velocity is directly proportional to the ionic mobility (μ) at a fixed value of applied dc potential.

Temperature dependent ionic conductivity and mobility studies of hot-pressed solid polymer electrolytes

Temperature dependent ionic conductivity (σ), ionic mobility (µ), and mobile ion concentration (n) of the hot-pressed Solid Polymer Electrolytes (SPEs): (1-x) PEO: x NaBr, where 0 < x < 50 in wt. %, has been reported. SPE films have been casted using a hot-press technique in place of the traditional solution cast method. A conductivity enhancement of the two orders of magnitude was achieved in SPE film composition: (70PEO: 30NaBr) at room temperature and this has been referred to as Optimum Conducting Composition (OCC). To determine the activation energy (Ea), energy of migration (Em) and energy of formation (Ef) temperature dependent studies of SPE OCC have been carried out with the help of various experimental procedures.

Synthesis and Characterization of Hot-Pressed Solid Polymer Electrolytes

Synthesis and ion transport characterizations on hot-pressed solid polymer electrolytes (SPEs): (1-x) PEO: x KBrO 3, where x in wt. (%), are reported. The compositional (x) dependent conductivity (σ) studies revealed SPE film: (70PEO: 30KBrO 3) as the Optimum Conducting Composition (OCC) with room temperature conductivity σ ~ 4.36 × 10 -7 Scm -1 , which is more than two orders of magnitude higher than that of pure PEO. To understand the ion transport behavior in SPE films, the measurement on some basic ionic parameters viz. ionic conductivity (σ), ionic mobility (μ) and mobile ion concentration (n) have been carried out using different experimental techniques. Material characterizations were done with the help of XRD, SEM, DSC and TGA techniques. The activation energies (E a

Ion Transport Properties of Hot-Pressed Solid Polymer Electrolytes: (1-x) PEO: x NaHCO3

Ion transport properties of hot-pressed Solid Polymer Electrolyte (SPE) membranes: (1-x) PEO: x NaHCO3, where x = 0 – 50 wt. (%), has been reported. SPE films have been casted using a hot-press technique in place of the traditional solution cast method. A conductivity enhancement of the two orders of magnitude was achieved in SPE film: 70PEO: 30NaHCO3 and this composition has been referred to as Optimum Conducting Composition (OCC). Materials characterization was done with the help of FTIR and DSC techniques. The ion transport behavior in SPE membranes have been discussed on the basis of experimental measurements on their ionic conductivity ( ) and other parameters. The temperature dependent conductivity studies have also been done to compute the activation energy (Ea) values by least square linear fitting of ‘log – 1/T’ Arrhenius plots.