Thermodynamics and defects of solids M1

This module is devoted to delivering basic knowledge on the thermodynamics of defects. Understanding the basic concepts of defects in stoichiometric and non-stoichiometric solids is an important aspect of better understanding and designing materials for ionic and electronic conductivity, with specific relevance for energy materials. The lecture introduces and discusses the nature of point defects that intrude upon the perfect geometry of ideal crystal structures:

• Introduction to point defects (missing or misplaced atoms, ions, or electrons)
• Discussion of thermodynamic concepts of order-disorder phenomena in solid solutions
• Understanding of Brouwer diagrams for oxides in order to emphasize the role of the surrounding atmosphere on defect equilibrium at high temperatures.
• Understanding of diffusion pathways and energies of ions and electrons, as a major consequence of point defects, giving rise to electrical transport is investigated for ionic conductors.
• Experimental investigations of measuring ionic conductivity versus temperature are described. The method of impedance spectroscopy measurements is discussed.
• Presentation of the Kröger-Vink Notation of defects
• Mott-Hubbard insulators

Hourly volumes:

CM: 24

TD: 12

Understanding the role of point defects in solids on transport properties and structural stability.

To apply the concept of Brouwer diagrams to control conductivity in oxides.

Electronic and ionic conductivity in metallic oxides

Understanding concepts of ceramic semiconductors

CC

- Ceramic (oxide) materials with metallic conductivity

- Defect chemistry (explaining properties of semiconductors and ionic conductors)

- Crystal-field splitting of d-orbitals

- Strong electron correlation (Coulomb repulsion)

- Structural instabilities (Peierls distortion)

- Anderson localization (electron localization when impurities or defects concentration is large)

- Mott-Hubbard insulators

- Ceramic semiconductors

- point defects

- extended defects

- Presentation of the Kröger-Vink Notation of defects

- Ionic conductors. Solid oxide fuel cells. Batteries.

- Brouwer diagrams and defect equilibrium at high temperature

- Understanding of diffusion pathways and energies of ions and electrons, as a major consequence of point defects, giving rise to electrical transport is investigated for ionic conductors.

- Experimental investigations of measuring ionic conductivity versus temperature via impedance spectroscopy measurements

Administrative contact(s): Master's in Chemistry Secretariatmaster-chimie@umontpellier.fr