R. H. Y. Subban

Polymer batteries fabricated from lithium complexed acetylated chitosan

Abstract It is found that 0.8 g lithium nitrate added to a solution of 1 g chitosan dissolved in 100 ml 1% acetic acid produces a film, via the solution cast technique, with a maximum electrical conductivity of the order of 10−4 S cm−1. This film is amorphous. For battery fabrication, metal powder and hydrogen storage material are used for the anode, and a metallic oxide (MnO2) for the cathode material. The anode contains a mixture of zinc and zinc sulfate in the ratio of 3:1. Batteries with configurations Zn + ZnSO4·7H2O/LiCAC/I2 + C and Zn + ZnSO4·7H2O/ LiCAC/MnO2+C (LiCAC = lithium complexed acetylated chitosan) provide open-circuit voltages of 1.113 and 0.765 V, respectively. The discharge characteristics of the batteries are presented. Unfortunately, only short lifetimes and small discharge currents can be obtained. This is possibly due to incompatibility between the electrode materials and the electrolytes.

Electrical conductivity studies on PVA/PVP-KOH alkaline solid polymer blend electrolyte

A series of conducting thin-film solid electrolytes based on poly (vinyl alcohol)/ poly (vinyl pyrrolidone) (PVA/PVP) polymer blend was prepared by the solution casting technique. PVA and PVP were mixed in various weight percent ratios and dissolved in 20 ml of distilled water. The samples were analyzed by using impedance spectroscopy in the frequency range between 100 Hz and 1 MHz. The PVA/PVP system with a composition of 80% PVA and 20 wt.% PVP exhibits the highest conductivity of (2.2±1.4) × 10−7 Scm−1. The highest conducting PVA/PVP blend was then further studied by adding different amounts of potassium hydroxide (KOH) ionic dopant. Water has been used as solvent to prepare PVA/PVP-KOH based alkaline solid polymer blend electrolyte films. The conductivity was enhanced to (1.5 ± 1.1) × 10−4 Scm−1 when 40 wt.% KOH was added.

Polymer batteries with chitosan electrolyte mixed with sodium perchlorate

Abstract 1 g chitosan was dissolved in 100 ml of 1% acetic acid solution. The solution was then mixed with sodium perchlorate. This chitosan-acetic acid-sodium perchlorate solution was then made into a thin film by the solution cast technique. Eight films were prepared each containing 1 g of chitosan in 100 ml of 1% acetic acid solution and 0.5 g, 1.0 g, 1.5 g, 2.0 g, 2.5 g, 3.0 g, 3.5 g and 4.0 g of sodium perchlorate (NaClO 4 ) respectively. The electrical conductivity of the films measured at room temperature stops increasing after more than 3.0 g of sodium perchlorate was added. We have attempted to explain this maximum in electrical conductivity in terms of the weak electrolyte theory. The film containing 3.0 g sodium perchlorate having the highest electrical conductivity of 4.6 × 10 −2 mS cm −1 was used in Zn + ZnSO 4.7 H 2 O/chitosan film/ X, where X is a metallic oxide such as PbO 2 , V 2 O 5 and MnO 2 . The internal resistance of these batteries are of the order of 10 3 ohms and is comparable with some of the polymer batteries that have been reported in the literature.

Effects of plasticiser on the lithium ionic conductivity of polymer electrolyte PVC-LiCF3so3

Solid polymer electrolyte films based on poly(vinyl chloride)-lithium triflate (PVC-LiCF3SO3) have been prepared by the solution-cast technique in various concentrations. The film with the highest conductivity was used to prepare plasticised polymer electrolyte films by using poly(ethlene glycol) (PEG) of different molecular weights, i.e., 200, 400 and 600 gmol−1. These films were prepared to study the effects of addition of low molecular weights PEG on the lithium ionic conduction of the PVC based polymer electrolyte. The films were characterised by electrochemical impedance spectroscopy (EIS) and Fourier transform infrared-spectroscopy (FTIR). Results indicate that the molecular weight has an inverse effect on the conductivity and this has been accounted for by FTIR.

Sodium iodide added chitosan electrolyte film for polymer batteries

Films of chitosan containing sodium iodide were prepared by the solution cast technique. Several films were prepared by dissolving 1 g of chitosan in different 100 ml of 1% acetic acid solution to which 0.5 g, 1.0 g, 1.5 g, 2.0 g and 2.5 g of sodium iodide was added. The electric conductivity of the films measured at room temperature stops increasing after more than 1.5 g of sodium iodide was added. The film with the highest electric conductivity of 4.9 × 10−2 mS/cm was used as an electrolyte to fabricate some thin film solid state batteries with the configuration Zn + ZnSO4 7H2O/electrolyte/X, where X is a metallic oxide such as PbO2, V2O5 and MnO2. The internal resistance of the fabricated batteries are comparable with the internal resistance of batteries reported in the literature.

Properties of PEMA-NH4CF3SO3 added to BMATSFI ionic liquid

Polymer electrolyte films, comprising ammonium trifluoromethanesulfonate salt and butyl-trimethyl ammonium bis(trifluoromethylsulfonyl)imide ionic liquid immobilized in poly (ethyl methacrylate) was studied. Structural, morphological, thermal and electrical properties of the polymer electrolyte films were investigated by differential scanning calorimetry, scanning electron microscopy, and impedance spectroscopy, respectively. Interactions of the salt and ionic liquid with the host polymer were investigated by Fourier transform infra-red spectroscopy. Electrochemical stability of the electrolytes was determined using linear sweep voltammetry and transference numbers corresponding to ionic transport has been evaluated by means of the Wagner polarization technique. The highest conductivity achieved is in the order of 10−4 S cm−1 for the film added with 35 wt % butyl trimethylammonium bis (trifluoromethanesulfonyl)imide. The film has high amorphicity and low glass transition temperature of 2 °C. The film is electrochemically stable up to 1.8 V. The ion transference number in the polymer film is 0.82 and the conductivity behavior obeys Vogel-Tamman-Fulcher equation.

ELECTRICAL PROPERTIES OF PEO-LiCF3SO3-SiO2 NANOCOMPOSITE POLYMER ELECTROLYTES

Abstract Nanoparticle oxide fillers such as SiO2 have been previously shown to affect the properties of polymer electrolytes, especially those based on polyether–lithium salt systems. In this work nanocomposite solid polymer electrolyte films composed of polyethyleneoxide (PEO), lithium triflate (LiCF3SO3) and SiO2 nanofiller (15 nm in size) have been prepared by using solution cast method. At room temperature, the sample 80PEO–20LiCF3SO3 (wt-%) was found to have the highest conductivity of about 2·04 × 10–7 S cm–1. The 88PEO–LiCF3SO3–12SiO2 (wt-%) has high ionic conductivity of about 1·28 × 10–3 S cm–1 at room temperature. The effects of concentration of filler on the dielectric properties of the electrolytes were also studied. Temperature effects on the dielectric properties revealed that the electrolytes to be of the non-Debye type.

Electrical Properties of Plasticized Chitosan-Lithium Imide with Oleic Acid- Based Polymer Electrolytes for Lithium Rechargeable Batteries

Solid polymer electrolytes (SPEs) were prepared and their electrochemical characteristics were characterized. The composition of SPEs containing chitosan, lithium trifluoromethane sulfonimide (LiN(CF3SO2)2) and oleic acid (OA) was optimized employing ac impedance measurements at various temperatures. The electrical conductivity of the SPEs with OA shows the highest value and the presence of OA does not change the structure of the polymer.

Impedance spectroscopic studies on a binary salt poly (vinyl chloride) based electrolyte

Polymer electrolyte membranes comprising poly vinyl chloride (PVC), lithium triflate (LiCF3SO3) and lithium hexafluorophosphate (LiPF6) were prepared using the solution-cast method. Impedance spectroscopy of these films was performed in the frequency range between 40 Hz to 1000 kHz at room temperature. X-ray diffraction studies indicate that complexation has taken place mainly in the amorphous phase. Further impedance spectroscopy response quantities such as complex dielectric constant and dielectric moduli were computed from the complex impedance. Conductivity dependence on temperature was studied for several films and the results are discussed.

Ionic Conductivity of PVC-NH4I-EC Proton Conducting Polymer Electrolytes

Poly(vinyl) chloride (PVC)-NH4I-EC films have been prepared by solution cast technique. The sample containing 30 wt. % NH4I exhibited highest room temperature conductivity of 4.60 × 10-7 S cm-1. The conductivity increased to 1.08 × 10-6 Scm-1 when 15 wt. % of ethylene carbonate (EC) was added to 70 wt. % PVC - 30 wt. % NH4I. Fourier Transform Infrared (FTIR) showed evidence of polymer–salt complexation while DSC showed increase in glass transition temperature (Tg ) of PVC -NH4I - EC polymer electrolytes. The conductivity behavior of the studied system could be accounted by the changes in Tg values.