Department of Physics
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Item Synthesis of Metal-Organic-Framework Derived Materials for Energy Storage Applications(2021) Ayesha; CIIT/FA19-RPH-026/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 7267With the progress in industrialization, the scarcity of resources and environmental pollution is growing fast. On the one hand, carbon dioxide produced by the ordinary combustion vehicle is a major source of global warming, where the fuel cars are accounted to consume a huge amount of oil resources. On the other hand, as the world has realized the importance of environmental protection, the development of a low- carbon transportation system has become an important solution. The electric vehicle has brought a lot of benefits, such as environmentally friendly, clean and no pollutant emissions. As a result, it might be regarded a potential new energy vehicle that has piqued the interest of consumers, industry, and researchers. Supercapacitors were also known as ultra-capacitors are being evaluated as one of the viable energy storage choices for future generations. These gadgets have been found to be useful in a range of applications, namely powering hybrid electric/electric automobiles and other electrical and electronic devices that enable energy to perform. Supercapacitors are the most flexible devices, widely used for supplying electrical energy quickly and in applications that need a long shelf life. As a result, there are considerable market demands for supercapacitors' development, and long-term advancement is necessary for their successful improvement and commercialization. New electronic and optoelectronic gadgets have recently grown on the market, requiring more dependable power sources with higher energy density and longer duration. Owing to their, pollution-free nature, stability, and high power density, supercapacitors have emerged as feasible options for energy storage. Traditional supercapacitors' poor energy density prevents them from being widely used, leading researchers to look into new forms of supercapacitors with better performance. Increasing the electrochemical performance of supercapacitors through the development of innovative electrode materials has been a major focus of study in recent decades. Asymmetric supercapacitors (ASCs) made consisting of two different electrode materials have a large working voltage window, enabling them to substantially increase energy density. In this research work, asymmetric super-capacitors electrode (ASCs) has been fabricated using Metal-Organic-Frameworks (MOF) derived mixed metallic oxides @CC as a positively charged electrode and MOF-derived nanoporous carbon (NPC) based material as a negatively charged electrode by a cost-effective hydrothermal method. The substantial materials are zinc-cobalt nitrates and 2-methylimidazole. The hydrothermal method is used to produce all samples.Item The Electrochemical Role of Mixed Valence Manganite for Fuel Cells(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) Bushra Bibi; CIIT/FA19-RPH-011/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 7261In this era renewable energy sources are becoming more important. They will play and anticipate a more vital role in near future to avoid atmosphere changes. In this context, fuel cells have gained much attention due to their high conversion efficiency when contrast with conventional energy conversion system. Among all the fuel cells, solid oxide fuel cell (SOFC) is one of the best sources for energy conversion technologies along with low toxic emission, pollution, fuel flexibility, and cost effective materials characteristics. However, there are still some complications that need to be addressed; one of the significant challenges, activity of SOFC at low temperature is decreased because of interfacial polarization obstructions and also oxygen reduction reaction (ORR). Thus to improve the activity and ORR, Strontium substituted lanthanum Manganite La1-xSrxMnO3 perovskite type cathode materials is synthesized. The prepared materials are Strontium substituted lanthanum Manganite (La1-xSrxMnO3) (LSM)) where x=0, 0.2, 0.4, 0.6, 0.8, 1.0 All samples are prepared by sol gel method. The functionalities of cathode materials (La1-xSrxMnO3) (LSM)) is investigated in this research. Prominent bands at peak positions 310, 456, 643, 990 cm −1 wavelengths are observed through Raman spectra of LSM cathodes, analogous to Mn-O-Mn bonds typical stretching, asymmetric stretching vibrations for Sr-O band. The prominent peaks at 650, 855, 1052cm -1 wavelengths observed through FTIR Analysis, these peaks attributed to stretching vibration of La-O bond, V1mode of carbonate ion, symmetric vibration of Sr-O bond. The band gap energy of material has been calculated 4.18 eV, 4.2 eV, 4.19 eV and 4.21 eV of La1Mn1O3, La0.8Sr0.2Mn1, La0.6Sr0.4Mn1 and La0.4Sr0.6Mn1respectively. These show that the band gap increases with the increase of the Sr 2+ ions concentration. DC Conductivity measurements of LSM cathode samples are evaluated by four point probe method. The La0.8Sr0.2Mn1O3–δ (LSM)has maximum conductivity of 0.726 Scm -1 at 600 °C .The effects of synthesized LSM materials on performance for Solid Oxide Fuel Cell (SOFC) cathode were studied. The results indicate that developed LSM materials are good cathode for SOFC as they have adequate electrocatalytic properties and good chemical stability.Item Multi Doped Ceria based Electrolyte for Low Temperature Solid Oxide Fuel Cell(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) UMAR ALI; CIIT/FA19-RPH-008/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 7244Energy conversion devices are widely being used to convert chemical into electrical. Fuel cell is the most prominent candidate among all the energy conversion devices. The operating temperature of conventional fuel cell is very high because of high electrolyte resistance. Develop better energy storage and conversion devices is the main goal of the scientists and engineers because of increasing global temperature due to consumption of fossil fuels. Fuel cell has potential and capability to give maximum energy without deteriorating environment. Electrolyte is the most important component of fuel cell because oxygen ion conduction only takes place through it. Electrolyte can be made more efficient by doping multi elements in it. In this research work, effects of multi doping in Ceria based electrolytes are discussed for Solid Oxide Fuel Cell. The focus of this project is to synthesize efficient electrolyte material which gives maximum oxygen ions conduction for better performance of fuel cell. Multi transition metals like Ca, Sm, Gd, Ga and Ba is doped with Ce in different composition via sol-gel and co-precipitation method. Four compositions are considered as Ce0.8 Gd0.1 Ba0.05 Ga0.05, Ce0.8 Ca0.1 Ba0.05 Ga0.05, Ce0.8 Sm0.1 Ba0.05 Ga0.05 and Ce0.8 Ca0.03 Gd0.03 Sm0.03 Ba0.05 Ga0.05. Different properties of the synthesized materials like ionic conductivity, crystal structure, optical properties bandgap and other properties have been checked. High ionic conducting is expected by above mentioned compositions. To increase the efficiency of energy conversion and storage devices doping behavior of materials is essential to study. Ceria based electrolytes gives much better performance as compared to conventional electrolyte materials like yttria stabilized zirconia. Ceria based electrolytes work in between intermediate (600-800 oC) to low temperature (400-600 oC). Operating temperature of conventional materials is above 1000 oC due to which efficiency of synthesize material decreases and stability of material also decreases. Crystalline structure of the material is determined by XRD, surface morphology of prepared material is analyzed by SEM, energy band gap can be found by Uv-Vis, vibrational characteristics and phase shift of the synthesized material can be found by Raman spectroscopy, materials used in synthesis can be confirmed by FTIR. In the end conductivity and fuel cell performance is checked. x