Synthesis and electrochemical characterization of low cost advanced fuel cell for polygeneration applications

Abstract

Synthesis and Electrochemical Characterization of Low Cost Advanced Fuel Cell for Polygeneration Applications The current assets of the world in terms of fossil fuels are depleting quickly due to high consumption rate. The world’s challenge is to determine the most efficient, economical, and environment friendly energy sources to compete and replace the ongoing conventional energy resources. In the past era, lots of efforts have been made by researchers to find out alternative energy resources to accomplish the demand of the coming generations. Polygeneration has been considered as one of the most favorable technologies to fulfill the heating and electrical demand simultaneously from single source (fuel) more efficiently. Among different polygeneration technologies, fuel cell can be considered one of the best promising technologies for power applications and has great consequences in energy conversion sector. A fuel cell is an energy conversion entity converting the fuel (in gaseous form) into heat and electric power through electro-chemical combination of fuel in the presence of an oxidant (normally air). Solid Oxide Fuel Cell (SOFC) is one such technology that is the most efficient and environment-friendly technology for generation of electric power due to terrific tolerance to impurities, cheap components materials, and fuel flexibility. Conventional work on SOFC is at high-temperature of 800-1000oC, where yttria stabilized zirconia (YSZ) electrolyte is used to gain necessary high ionic conductivity. Because of this high operational temperature, SOFC faces hurdles in commercialization as it causes the thermal expansion mismatch, cell components degradation, and little choice of materials, etc. In order to use SOFC commercially, it is essential to decrease its operational temperature and its cost. The thesis main focus is to find out the solution and motivation towards minimizing operating temperature and lower the operating cost of fuels for SOFCs. In this research, modifying approach is used in materials to reduce working temperature and to develop multi-fuel (hydrogen, natural gas, ethanol, glucose, and sugar-cane) based SOFCs. Numerous electrode and electrolyte materials have been developed to get better results (conductivity and performance) by using hydrogen as well as xi hydrocarbon fuels in this study. The research work has been categorized into three parts; In first part of the thesis where electrolytes and electrodes are synthesized and electrochemically characterized through H2 fuel only, on behalf of the obtained electronic conductivity, OCV, and power density including nano-structuring technique, the Ag0.25Ti0.05Zn0.70 and GDC-AlZnCa materials can be considered one of the best alternative cheap anode and electrolyte for intermediate temperature SOFCs. In second part of the thesis where electrochemically characterization was carried out in presence of multi-fuels i.e. hydrogen, natural gas, ethanol, glucose and sugar-cane, and the current study reveals that proposed anode Ni0.6(Ba0.3Ce0.2Zn0.5)0.4 is promising multi-fuel anode material for low-temperature solid oxide fuel cell, and it does not need to reform hydrocarbon fuels in order to fully utilize the advantage of these cells. In third part of the thesis, the experimental results are validated through modeling and simulation with the help of COMSOL