Synthesis, Structure and Proton Conduction of Substituted BaTiO3 and BaZrO3 Perovskites
Doktorsavhandling, 2013

Proton conducting oxides can be beneficial as electrolyte materials in devices such as fuel cells, hydrogen sensors etc. Proton conducting fuel cells (PCFCs), utilising H2 as fuel, stand out as a promising technology for future clean energy generation. The works herein is devoted to improve the performance of current state of the art perovskite structured BaZrO3 based electrolyte materials as well as synthesise and characterise novel electrolytes within the BaTiO3 based systems. Usually acceptor doping of these perovskites allows for proton conductivity in hydrogen containing atmosphere. In this thesis heavily co-doped strategy along with the impact of addition of sintering aid (ZnO) and various synthesis routes in BaZrO3 based materials is being tested. Heavily doped BaTiO3 based systems are also synthesised for the first time and characterised with an emphasis on proton conduction. This work is based on techniques such as X-ray powder diffraction studies, neutron powder diffraction, thermogravimetric analysis and AC impedance spectroscopy. In addition a neutron total scattering study is employed for the first time to understand the local structural environment for the deuteron position in a proton conducting electrolyte. Co-doping and sintering aid (in solution synthesis) for the In/Yb:BaZrO3 electrolyte seems to be beneficial. Heavily substituted Sc/In:BaTiO3 materials also show enhanced proton conductivity.

deuteron position

Rietveld refinements

heavily doped oxygen deficient perovskite (BaTiO3/ BaZrO3)

neutron total scattering

New proton conductor

X-ray and neutron powder diffraction

RMC modelling.

Impedance spectroscopy

10:an, Kemivägen 10, Chalmers University of Technology
Opponent: Dr. Stephen Skinner, Imperial College London, England.


Seikh Mohammad Habibur Rahman

Chalmers, Kemi- och bioteknik

50 mol% indium substituted BaTiO3: Characterization of structure and conductivity

International Journal of Hydrogen Energy,; Vol. 37(2012)p. 7975-7982

Artikel i vetenskaplig tidskrift

Proton Conductivity in Mixed B-Site Doped Perovskite Oxide BaZr[sub 0.5]In[sub 0.25]Yb[sub 0.25]O[sub 3 - delta]

Journal of the Electrochemical Society,; Vol. 157(2010)p. B1819-B1824

Artikel i vetenskaplig tidskrift

Synthesis and Enhanced Proton Conduction in a 20 mol% Ytterbium Doped Barium Zirconate Ceramic Using Zn as Sintering Aid

Applied Mechanics and Materials,; Vol. 110-116(2012)p. 1181-1186

Paper i proceeding

Among various types of fuel cells, the high temperature proton conducting fuel cell (PCFC), in particular, has some advantages compared to others. In order to see successful and sustainable application of PCFC in the near future, some material challenges need to be overcome. Apart from having adequate proton conductivity, development of fabrication processes for thin (1-5 µm), leak-free electrolytes on a porous electrode support with acceptable chemical and mechanical stability is a must. Moreover, there is a need for improved electrode materials; especially research on PCFC cathode materials must make progress. In this study, various strategies are undertaken in order to improve the proton conductivity of state of the art electrolyte materials such as acceptor doped BaZrO3. In addition, synthesis and characterisation of BaTiO3 based materials is undertaken as a new candidate electrolyte. Structure-property relations are also looked into within these materials. Improved conductivity has been obtained within the zirconate based systems. On top of this, the synthesis of new titanate based materials, with promising proton conductivity has been accomplished. Additionally, neutron total scattering study has been performed, for the first time, in order to comprehend the local proton environment within an oxide based proton conducting electrolyte material.


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Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie

10:an, Kemivägen 10, Chalmers University of Technology

Opponent: Dr. Stephen Skinner, Imperial College London, England.