Preparation And Performance Study Of Direct Carbon Solid Oxide Fuel Cells Using Lignite As Fuel

Take a view of today’s world,the energy crisis and environmental pollution are becoming increasingly serious.Traditional power generation by coal-fired thermal will emit a large amount of greenhouse gases,and will face challenges such as the price of emissions rights and the decline in social recognition in some parts of the world.These have forced us to find and develop clean utilization technologies for fossil fuels.Direct carbon solid oxide fuel cells（DC-SOFC）are one of the solutions for clean energy utilization.It is a kind of direct carbon fuel cell（DCFC）with an all-solid structure of oxygen ion conductor as electrolyte.It is an energy conversion device that can directly convert solid carbon fuel into electrical energy through electrochemical oxidation.This paper focuses on the practical application of Xuanwei brown coal resources in direct carbon solid oxide fuel cells,explores the feasibility of brown coal as a DC-SOFC’s fuel,and devotes a series of studies to improve its output performance.It provides a green way for the use of brown coal in power generation provides.Related research results are as follows:First,the feasibility of DC-SOFC using brown coal as fuel is analyzed and its reaction mechanism is preliminary studied.Using nano-Al₂O₃ doped yttrium-stabilized zirconia（YSZ）as the electrolyte and Ag-Gd_0.1Ce_0.9O_2-δ（Ag-GDC）metal-based ceramic composite material as a symmetric catalyst electrode,single cell of DC-SOFCs was prepared ith Ag-GDC/YSZ/Ag-GDC as its structure.Using raw brown coal and char derived from brown coal as fuel and operated at a temperature of 850°C,the cells can get a maximum power density of 211.4 and 221m Wcm^-2,respectively.In addition,when the DC-SOFC using char derived from brown coal as fuel was operated at a constant current of 0.1 A,it showed a stable discharge voltage and platform,and the fuel utilization rate reached 61.5%.Further analysis shows that the superior performance and high carbon utilization rate of the excellent direct brown coal fuel cell is attributed to the high-efficiency catalytic activity of the composite Ag-GDC catalytic electrode and the naturally-supported Ca²⁺and other alkali metals in the fuel itself which became an excellent catalyst for reverse Boudouard reaction.Then,we searched for a new type of natural loaded reverse Boudouard reaction catalyst material through the way of graduate biomass char materials,and optimized the treatment of brown coal.Porous biomass carbon was obtained by pyrolysis and loaded into brown coal fuel,effectively improving the output performance of DC-SOFC using brown coal as fuel.Using kelp biochar-doped char derived from brown coal as fuel,the maximum output power at 800 and 850℃can reach 181.2 and 296.4m W cm^-2,respectively.Compared with a single cell using char derived from brown coal as fuel,the performance has been significantly improved.Natural marine biomass can provide excellent reverse Boudouard reaction catalyst components for the DC-SOFC fuel side,which provides new ideas for future research.In summary,it is still the most direct and effective way to improve their performance by optimizing traditional coal fossil fuels,adapting suitable fuel cell materials and actively looking for efficient direct coal solid oxide fuel cell catalysts.This paper systematically studied the pyrolysis of brown coal,the preparation of natural biomass carbon and brown coal composite fuel,and the optimization of the performance of direct carbon solid oxide fuel cells using brown coal as the fuel,and it provide theoretical and experimental basis and technical reserves for the clean and efficient use of brown coal and other coal resources.