Nazrin Abdullayeva is currently a PhD student in the Materials Science and Nanotechnology Engineering Department at the TOBB University of Economics and Technology (TOBB ETU), Ankara, Turkey. She has graduated from the Department of Chemical Engineering of Hacettepe University, Ankara, Turkey in 2015. She has received her Master’s degree in Materials Science and Nanotechnology Engineering from TOBB University of Economics and Technology (TOBB ETU), Ankara, Turkey in 2017. She has carried out researches in the field of conductive polymers and ionomers, photovoltaic devices, semiconductor materials and thin film solar cell applications.
Redox flow batteries (RFBs) constituting a large space in the electrochemical systems used in energy storage purposes are best known for their long-lasting life services, simple manufacturing, low cost and safety properties. Li-flow batteries being a representative of aqueous RFBs has a potential of becoming one of the major used battery types for its suitable and higher voltages in contrast to other RFBs based on proton chemistry. In Li-flow batteries, membrane acts as the separating layer between two electrolyte compartments that prevents the crossover of the charged molecules. The suitable membrane selection is a crucial factor that strongly affects the efficiency of the device. As far as we know, NafionTM has been widely used in the flow battery systems, so far. However, there is no significant study performed in the field of membrane optimization for Li RFBs. Herein, for the very first time we introduce disulfonated poly (arylene ether sulfone) (BPSH) copolymers as an alternative membrane for Li RFBs. Sodium form of copolymer has successfully been converted into acid and lithium forms. Fundamental material characterizations such as FTIR), Raman, TGA, AFM, H+ and Li+ conductivities, cyclic voltammetry and performance evaluations have been widely studied to identify chemical, electrochemical and structural properties of the membranes. Additionally, the influence of basic membrane properties such as water uptake, proton conductivities and the ion exchange capacities on the Li ion transport has been investigated. It has been shown that a correlation exists between the conductivity of lithiated membranes and molarity of conducting solution. The highest lithium conductivity was measured as 39.07 Scm-1 at 1M LiClO4 solution. Moreover, the degree of the chemical interaction of Li+ ions with the sulfonate functional groups has been demonstrated by several methods such as FTIR and RAMAN studies. The FTIR peak shift at 1140 cm-1 and Raman shifts at 1155 cm-1 corresponding to the S=O symmetric stretching represent the interaction taking place between Li+ ions with the membrane. AFM studies has revealed that hydrophilic and hydrophobic domains have been well defined for acid and salt (Li+ and Na+) form of the membranes.
Fatima Al Hameli has completed her graduation from Petroleum Institute, Abu Dhabi UAE with a Bachelor’s degree in Chemical Engineering in 2012. She has worked as a Senior Lab Technician for 3 years in the Microscopy Department of Borouge Ptv. Ltd. Innovation Center, which focused on developing new polymeric material for the market. Currently she is pursuing a Master’s degree in Khalifa University (Masdar Institute branch) in Materials Science and Engineering Department.
Solar energy is one of the most readily accessible sources of renewable energy that may be utilized in the United Arab Emirates. Yet at the same time the UAE has one of the most severe weather conditions as it has a harsh desert climate with high amounts of dust, and temperatures may reach up to 50 °C in the summer. Sand and tiny pebbles accumulate on solar panels forming small scratches on the coating surface resulting in reduction of its mechanical and optical properties, therefore reducing the potential maximum energy output. A proposed solution is the application of an epoxy coating with self-healing properties. Self-healing materials are commonly classified as either autonomic or non-autonomic materials. To benefit from both approaches this project will aim at utilizing both capsule based and intrinsic self-healing. The project also aims at utilizing the high temperatures of the UAE to act as the external stimulus to activate the intrinsic self-healing. The proposed self-healing coating is achieved by adding cellulose acetate butyrate (CAB) as the intrinsic healing agent and using halloysite nanotubes (HNT) to sequester healing agents as the capsule based approach. Various concentrations of CAB in epoxy are tested to obtain the best concentration for complete healing. Multiple healing temperature and time are also tested to obtain the optimum healing conditions. Samples were tested in outdoor conditions to study the effect of the weather and dust on the samples. Based on thermal and mechanical tests for complete healing of the material the optimum composition is an epoxy composite with 3 vol% CAB and 1 vol% HNT and the optimum healing temperature is 110 °C. Outdoor testing was carried out for three months during winter until the samples failed due to delamination. The addition of CAB provided improvement to the epoxy material to withstand weather conditions.