C8514 - PHYSICS OF ENERGY MATERIALS

Learning outcomes

By the end of the course, students will learn the microscopic physical mechanisms that govern energy conversion and storage in materials, such as photovoltage generation, charge and mass transport, interfacial kinetics, and phase transformations. They will be able to apply quantitative models and practical examples to evaluate the performance of energy devices, including solar cells, thermoelectric converters, hydrogen storage materials, and photoelectrochemical systems, and to assess the advantages and limitations of different materials strategies used for their implementation.

Course contents

From fundamental physical principles to energy conversion and storage technologies

The course provides a unified physical framework for understanding the microscopic mechanisms governing energy conversion and storage in materials. Rather than presenting individual technologies separately, it develops the fundamental concepts of thermodynamics, transport, kinetics, optoelectronic processes and surface physics, illustrating how the same physical principles underpin a broad range of modern energy technologies.

The contents of Module 2 are written in italic below.

Topic 1 – Thermodynamics of Energy Materials

Review of equilibrium thermodynamics of condensed systems. Thermodynamic potentials. Chemical potential, electrochemical potential and Fermi energy. Phase equilibria and phase diagrams. van't Hoff equation and Nernst equation. Electrochemical equilibrium and Pourbaix diagrams.

Applications: Solid-state hydrogen storage, electrochemical energy storage

Topic 2 – Transport Fundamentals

Irreversible thermodynamics. Entropy production. Onsager reciprocity relations. Generalized thermodynamic forces and fluxes. Diffusion equation. Coupled transport phenomena. Thermoelectric effects.

Applications: Thermoelectric energy conversion.

Topic 3 – Atomistic Transport and Interfacial Kinetics

Transition state theory. Random walk and microscopic origin of diffusion. Atomistic diffusion mechanisms in solids and liquids. Diffusion of vacancies, interstitials and complex ionic defects. Membranes for ionic transport. Electrochemical kinetics: Butler–Volmer model. Multi-step electrode reactions. Marcus theory of charge transfer. Electrochemical impedance spectroscopy.

Applications: (solid-state) batteries, fuel cells, electrolyzers and electrodeposition of functional nanostructures.

Topic 4 – Surface and Gas–Solid Processes

Structure and energetics of solid surfaces. Capillarity forces. Classical theory of nucleation and first-order phase transformations. Physisorption and chemisorption. Hydrogen interaction with metals: absorption, diffusion and hydride formation. Introduction to the d-band model of surface reactivity.

Applications: hydrogen storage and compression by metal hydrides, heterogeneous catalysis

Topic 5 – Optoelectronic Processes for Energy Conversion

Generation and recombination of charge carriers in semiconductors. Light absorption and photovoltage generation. Basic structures of solar cells. Photoelectrochemical conversion of solar energy.

Applications: photovoltaic solar cells and light-emitting diodes, photoelectrochemical cells, dye-sensitized solar cells.

 

Readings/Bibliography

The slides and the lecture notes are available on Virtuale.

For further readings the following books are suggested:

R. DeHoff, Thermodynamics in Materials Science, Taylor and Francis

P. Würfel and U. Würfel, Physics of Solar Cells, Wiley-VCH

A. J. Bard and L. R. Faulkner, Electrochemical Methods: Fundamentals and Applications, John Wiley & Son

R.W. Balluffi, S.M. Allen, W.C. Carter, Kinetics of Materials, Wiley

Teaching methods

Frontal lectures, both at the blackboard and with the aid of a videoprojector. Interactive anonymous questionnaires to boost engagement.

Assessment methods

The exam consists of an oral interview of about 30-40 minutes.

The students begin by presenting a topic of their choice among those covered during the course. In-depth discussions developed independently by the student, based on the recommended bibliography or other scientific literature, are welcome but not mandatory. The presentation must be given at the blackboard or on paper, without slides or notes, and must not exceed 15 minutes. During the presentation, the instructor may ask questions to clarify or explore certain aspects of the topic. The presentation is expected to be thorough: the student should demonstrate knowledge of the mathematical derivations as well as a solid understanding of the physical principles and any approximations used.

Following the chosen-topic presentation, the instructor will ask the student to briefly discuss another topic from the course (see "Course Contents"). In this second part, the student is expected to demonstrate a good understanding of the main physical concepts, but derivations are not required. In particular, the student should be able to outline the initial assumptions, highlight any approximations, and explain how the results are applied.

Grading Criteria
The grade is awarded according to the following criteria:

• 29–30L: Thorough preparation on all topics, strong analytical skills, full command of subject-specific terminology

• 26–28: In-depth knowledge of the chosen topic and fair to good preparation on the rest; good analytical skills and use of appropriate terminology and language

• 22–25: Good preparation on the chosen topic and fair knowledge of the rest; analytical skills demonstrated mainly with guidance from the instructor; correct use of language

• 18–21: Fair preparation on the chosen topic and sufficient understanding of the rest; analytical skills emerging only with guidance; overall acceptable language.

The grade obtained following the oral exam may be rejected only once.

The use of AI during the oral assessment is strictly forbidden and will be considered a violation of the academic integrity.

Students with Specific Learning Disorders (SLD) or temporary/permanent disabilities are strongly advised to contact the University's dedicated office in advance (https://site.unibo.it/studenti-con-disabilita-e-dsa/en). This office will be responsible for proposing any necessary accommodations to the interested students. Such accommodations must be submitted to the instructor for approval at least 15 days in advance, and will be assessed in relation to the learning objectives of the course.

Teaching tools

The recorded lectures are available on Virtuale until the endof the exam session that follows the lecture period.

Office hours

See the website of Luca Pasquini

See the website of