Douglas Dahn

By Adam J. Proud, Rabin Bissessur and Douglas C. Dahn

Part of the book: Nanocomposites and Polymers with Analytical Methods

By Evans A. Monyoncho, Rabin Bissessur, Douglas C. Dahn and Victoria Trenton

We report, for the first time, the intercalation of poly[oligo(ethylene glycol) oxalate] (POEGO) and POEGO lithium salt (LiCF3SO3) complex (POEGO-LiCF3SO3) into vanadium pentoxide xerogel (V2O5nH2O). The effect of changing the polymer concentration on the interlayer expansion of the layered host was studied, and the optimal intercalation ratio was determined to be 1:2. The intercalates were characterized by powder X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, and AC impedance spectroscopy.

Part of the book: Alkali-ion Batteries

By Barrit C.S. Lane, Rabin Bissessur, Alaa S. Abd-El-Aziz, Wael H. Alsaedi, Douglas C. Dahn, Emma McDermott and Andrew Martin

Nanocomposite materials consisting of polyaniline (PANI) and exfoliated WS2 were synthesized. The WS2 was prepared by reacting tungstic acid with thiourea at 500°C under nitrogen flow. Samples were prepared with a WS2 content of 1, 5, 7.5, 10, 12.5, 15, 20, 37, and 64% by mass. An improvement in the electronic conductivity value of the PANI was observed through the incorporation of exfoliated WS2. The electronic conductivity of PANI-15%WS2 was 24.5 S/cm, an eightfold increase when compared to pure PANI. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) provided evidence that the nanocomposites are in an exfoliated state. XRD and TEM showed that the nanocomposites were completely amorphous, suggesting lack of structural order in these materials, while their EPR signals were considerably narrower compared to pure PANI, indicating the formation of genuine exfoliated systems. Furthermore, our research showed that WS2 can be used as a filler to improve activation energy of decomposition of the polymer. By using the Ozawa method, we studied the decomposition kinetics for the nanocomposites, as well as for the pure polymer. The activation energy for the decomposition of pure PANI was found to be 131.2 kJ/mol. Increasing the amount of WS2 to 12.5% in the PANI increases the activation energy of decomposition to 165.4 kJ/mol, an enhancement of 34.2 kJ/mol over the pure polymer.

Part of the book: Conducting Polymers

By Iskandar Saada, Rabin Bissessur, Douglas C. Dahn and Matthieu Hughes

Poly(bis-(methoxyethoxyethoxy)phosphazene) (MEEP) intercalated into lithium hectorite was investigated for its potential application as a solid polymer electrolyte in lithium-ion polymer batteries. Varying amounts of MEEP were intercalated into lithium hectorite, and the physical properties of the nanocomposites were monitored using powder X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, and attenuated total reflectance spectroscopy. Alternating current (AC) impedance spectroscopy was used to determine the ionic conductivity of the nanocomposites when complexed with lithium triflate salt.

Part of the book: Conducting Polymers