Development of a new manufacturing method of electrodes for solid oxide fuel cells

It is well established that anodes for solid oxide fuel cells (SOFCs) can be manufactured by processes involving final sintering. This research investigated a novel alternative method which relies on the electroless co-deposition of yttria-stabilised zirconia (YSZ) or ceria-stabilised zirconia (CeSZ) and nickel onto a YSZ substrate. This process allows complex or simple shaped substrates to be coated, thereby replacing the high temperature sintering and reduction stages with a single plating operation, which is substantially more cost effective and greatly simplifies the manufacture of any cell design. The technique also eliminates the production of larger nickel grains (which occurs during sintering), thus improving cell performance. Through a series of multifactoral experiments, a successful method was established and optimised for the deposition of the metal-ceramic composite which was successfully used in Solid Oxide Fuel Cell stack. The typical process involves degreasing and chemical pre-treatment of the substrates, followed by electroless co-deposition of the cermet coating, using either proprietary based chemicals or standard analytical reagents which have been specially formulated. Through the metallurgical examination of the experimental samples it has been shown that the ratio of the metal to ceramic can be varied, thus catering to a potentially large customer base, and that a composition gradient can be achieved through the coating. Additional parameters such as porosity and electrical conductivity have also been evaluated and the results have been so encouraging that there has been significant commercial interest in the process. Further work is continuing as part of a Proof of Concept (POC) project, with funding generously provided by Scottish Enterprise. Intellectual Property has been secured initially through funding supplied by Edinburgh Napier University, then subsequently through the POC project, with the aim that on completion of the project a spin-out company from Edinburgh Napier University is established.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Development of a new manufacturing method of electrodes for solid oxide fuel cells

It is well established that anodes for solid oxide fuel cells (SOFCs) can be manufactured by processes involving final sintering. This research investigated a novel alternative method which relies on the electroless co-deposition of yttria-stabilised zirconia (YSZ) or ceria-stabilised zirconia (CeSZ) and nickel onto a YSZ substrate. This process allows complex or simple shaped substrates to be coated, thereby replacing the high temperature sintering and reduction stages with a single plating operation, which is substantially more cost effective and greatly simplifies the manufacture of any cell design. The technique also eliminates the production of larger nickel grains (which occurs during sintering), thus improving cell performance.Through a series of multifactoral experiments, a successful method was established and optimised for the deposition of the metal-ceramic composite which was successfully used in Solid Oxide Fuel Cell stack. The typical process involves degreasing and chemical pre-treatment of the substrates, followed by electroless co-deposition of the cermet coating, using either proprietary based chemicals or standard analytical reagents which have been specially formulated.Through the metallurgical examination of the experimental samples it has been shown that the ratio of the metal to ceramic can be varied, thus catering to a potentially large customer base, and that a composition gradient can be achieved through the coating. Additional parameters such as porosity and electrical conductivity have also been evaluated and the results have been so encouraging that there has been significant commercial interest in the process.Further work is continuing as part of a Proof of Concept (POC) project, with funding generously provided by Scottish Enterprise. Intellectual Property has been secured initially through funding supplied by Edinburgh Napier University, then subsequently through the POC project, with the aim that on completion of the project a spin-out company from Edinburgh Napier University is established

Advanced Topics in Mass Transfer

This book introduces a number of selected advanced topics in mass transfer phenomenon and covers its theoretical, numerical, modeling and experimental aspects. The 26 chapters of this book are divided into five parts. The first is devoted to the study of some problems of mass transfer in microchannels, turbulence, waves and plasma, while chapters regarding mass transfer with hydro-, magnetohydro- and electro- dynamics are collected in the second part. The third part deals with mass transfer in food, such as rice, cheese, fruits and vegetables, and the fourth focuses on mass transfer in some large-scale applications such as geomorphologic studies. The last part introduces several issues of combined heat and mass transfer phenomena. The book can be considered as a rich reference for researchers and engineers working in the field of mass transfer and its related topics

Electrodeposition process modeling using continuous and discrete scales

Chemical bath electro deposition process is used in many industrial applications to obtain a thin layer material on a target surface. Numerous metal, magnetic or semi-conductor materials, such as oxide, chalcogenure or alloys are obtained in electrochemical cells at laboratory scale. Some of these materials are interesting to be produced at industrial scale, for example for electronics, fuel cells or photovoltaic applications. In industrial electrochemical cells, dimension is larger and many parameters such as hydrodynamics or electro active specie transport are heterogeneous. There are many industrial electrochemical techniques in which the electrode moves with respect to the solution. These systems, like the rotating electrodes, are called hydrodynamic electrochemical processes. It is also interesting to notice that micronic structure, such as roughness, columnar structure or porosity of material deposit is local flow dependent. Then, it appears, that the material deposit composition and structural quality need integrated information from the micronic scale to the industrial scale, using, of course, the laboratory scale measurements. The aim of the present work is to model and to numerically simulate the hydrodynamics, electrochemical and chemical coupled phenomena, which are occurring during the chemical bath electro deposition process for laboratory and industrial configurations. Experimental measurements obtained at laboratory scale with zinc oxide thin layer deposit are used to identify transport or kinetic data input which are conserved during the scale-up. Flow and chemical species concentration field properties are calculated in the working electrode surface vicinity taking into account homogeneous and heterogeneous reactions. The numerical method used is the finite volume method. In addition, using a Monte Carlo method, micronic information is calculated such as the roughness and the porosity of the thin layer material obtained