New Type Of Hydrocarbon Fuel For Intermediate Temperature Solid Oxide Fuel Cell Anode

Solid oxide fuel cell (SOFC) is an energy conversion device which produces electricity by electrochemical combination a fuel and an oxidant. SOFC has been developed rapidly in recent years due to their all-solid-state components, high efficiency, low pollution, and variety of fuels available. Despite being first commercial demonstration over 20 years ago, it is not successful to reach commercialization in SOFC so far due to its high operating temperature (~1000°C). Decreasing the thickness of electrolyte and developing novel electrolyte with higher ionic conductivity are the major approaches to lowering operating temperature to 600-800℃. Another limitation of conventional SOFC technology is the requirement that the fuel be hydrogen. Recently, many efforts have been made to operate SOFC directly on hydrocarbon fuels. To achieve good performance in such cells, anode materials with high catalytic activity toward electrochemical oxidation of hydrocarbons and good resistance for carbon formation are desirable, as well as the optimum operating conditions.This thesis aims to develop high performance anode for direct hydrocarbon utilization and optimize cell operating conditions by thermodynamic analysis. Another propose is to reveal the conducting mechanism of novel composite electrolyte.In chapter 1, the theory of SOFC was briefly introduced at first. The latest progress in the study of electrolyte materials, cathode materials, anode materials and interconnected materials has been reviewed. The development in anode materials for direct hydrocarbon SOFC was especially highlighted.In chapter 2, the electromotive force (e.m.f.) of solid oxide fuel cells (SOFCs) using biomass produced gas (BPG) as fuels is calculated to be between 700 and 1,200 K using an in-house computer program based on thermodynamic equilibrium analysis. Tour program also predicts the concentration of oxygen in the fuel chamber as well as the concentration of equilibrium species such as H2, CO, CO2 and CH4. Compared with using hydrogen as a fuel, the e.m.f. for cells using BPG as fuel is relative low and strongly influenced by carbon deposition. To remove carbon deposition, the...