1. Introduction to Electrochemistry

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Introduction to the Basics of Electrochemistry

This video is a good introduction to the basics of electricity, chemistry, and electrochemistry. If you do not have any prior experience with electrochemistry or chemistry, this would be good place to start. If you have solid grasp of the chemistry and the concept of electrochemistry, feel free to skip to the next video.

Introduction to the Fundamentals of Electrochemistry

The following videos introduce the fundamental aspects used in electrochemical methods, which will be covered in greater detail in subsequent lessons. Please note that you can download a copy of the slides here for notetaking purposes.

Brief Overview of Electrochemical Applications and History

If you are wondering why electrochemistry matters or how electrochemistry came to be, this video provides brief answers to both of those questions.

This video helps motivate and provide context for the learning ahead.

Electrochemical Terms and Conventions

Before we dive into the concepts, theory, and relations of electrochemistry, we need to be able speak and understand the same language. The basic terms (vocabulary) and conventions (grammar) of electrochemistry are presented in the video. It may also be useful to watch the Cell Notation video by Emily Tsui to understand the shorthand often used to represent electrochemical cells.

Brief Note of Types of Electrochemical Cells

Newcomers to electrochemistry often get confused about when to use the terms "anode" and "cathode" versus "working electrode" and "counter electrode." This confusion arises from the different types of electrochemical cells and their modes of operation. There are three main types of electrochemical cells (see image above):

1. Galvanic (or voltaic) cells: These cells have two electrodes and generate electricity from chemical reactions within the cell. Examples include batteries and fuel cells when discharging.
2. Electrolytic cells: These cells also have two electrodes but consume electricity to drive chemical reactions that produce a product. Examples include electrorefiners and electrolyzers. Batteries act as electrolytic cells when recharging.
3. Electroanalytical cells: These cells can have either two or three electrodes and are used to study electrochemical reactions. The potential and/or current at the electrodes can change, causing a single electrode to experience both oxidation and reduction.

In the image above, galvanic and electrolytic cells are represented by the general production cell. In galvanic and electrolytic cells, one electrode always undergoes oxidation (the anode), and the other always undergoes reduction (the cathode). However, in electroanalytical cells, the terms "anode" and "cathode" can be confusing because the roles of the electrodes can switch depending on the potential or current applied.

Instead, different terminology is used in electroanalytical cells:

• Working electrode (WE): This is the electrode being controlled and studied. On a potentiostat*, the WE carries the current.
• Sensing electrode (SE): Often used interchangeably with the working electrode, this is the electrode where the reaction of interest occurs. On a potentiostat*, the SE is couples with the WE and sense the potential of the WE.
• Counter electrode (CE): This electrode completes the electrical circuit, allowing electrons to flow without interfering with the processes at the working electrode.
• Reference electrode (RE): An electrode with a stable and well-known electrode potential. The WE potential is measured relative to or in reference to the potential of the RE.

Electroanalytical cells can operate as:

• 2-electrode cells: Consisting of a paired WE/SE and a paired CE/RE, used when negligible net current is flowing.
• 3-electrode cells: Consisting of a WE/SE, RE, and CE, used when appreciable net current is flowing to minimize the impact of current flow on potential measurements. A large resistor is wired between the WE and RE in the potentiostat* (see image above) to ensure minimal current flows between the two electrodes minimizing ohmic drop (See Overview of Resistance and Capacitance video below).

*Potentiostat: A potentiostat is an electronic device used in electrochemistry to control the voltage between the working electrode and the reference electrode in an electrochemical cell. It measures the current that flows between the working electrode and the counter electrode. This precise control and measurement are essential for studying electrochemical reactions and processes in electroanalytical cells. In contrast, galvanic and electrolytic cells usually do not require as precise of control and typically use power supplies (electrolytic cells) or a load (galvanic cells), like a motor, light, or your cell phone to either generate or consume electricity, respectively.

Overview of Electrode Potentials

This video discusses some of the fundamental process that play role in determining an electrode's potential.

Overview of Current in Electrochemical Cells

This video reviews the physical phenomena behind the measured current in electrochemical cells.

Overview of Resistance and Capacitance in Electrochemical Cells

Signals in electrochemical cell can also be impacted by resistance and capacitance. This video provides an overview of their impact.

Click here to go to Lesson 2: Electrochemical Potentials.

Additional Resources:

PDF of Slides from the Video for Notetaking:
Introduction to Electrochemistry Slides

Archived Videos:

These videos provide a little bit different approach and may discuss some topics in greater detail.
Old Convention and Terms Video
Old Overview of Electrode Potentials Video
Old Overview of Current Video

Electrochemistry Video by Emily Tsui:

Redox and Half-Cell Reactions - Introduces the concept of half-cell reaction from an overall redox reaction.
Cell notation - Covers the shorthand used to represent electrochemical cells, which may appear in some texts and videos.

References for Deeper and Broader Learning:

Electrochemical applications:

Read the first couple paragraphs of the Introduction of reference below. There several references cited in the first couple paragraphs as well, which can be explored as desired.

Williams, T., Shum, R., & Rappleye, D. (2021). Concentration Measurements In Molten Chloride Salts Using Electrochemical Methods. Journal of The Electrochemical Society, 168(12), 123510. https://doi.org/10.1149/1945-7111/ac436a

Electrochemistry History:

Shukla, A. K., & Kumar, T. P. (2008). ECS Classics: Pillars of Modern Electrochemistry. The Electrochemical Society Interface, 17(3), 31. https://doi.org/10.1149/2.F01083IF
Lubert, K.-H., & Kalcher, K. (2010). History of Electroanalytical Methods. Electroanalysis, 22(17–18), 1937–1946. https://doi.org/10.1002/elan.201000087
Laitinen, H. A. (1989). History of Electroanalytical Chemistry in Molten Salts. In Electrochemistry, Past and Present (Vol. 390, pp. 417–428). American Chemical Society. https://doi.org/10.1021/bk-1989-0390.ch028

Conventions, Terms, and Concepts:

Anson, F. C. (1959). Common sources of confusion; Electrode sign conventions. Journal of Chemical Education, 36(8), 394. https://doi.org/10.1021/ed036p394
Faulkner, L. R. (1983). Understanding electrochemistry: Some distinctive concepts. Journal of Chemical Education, 60(4), 262. https://doi.org/10.1021/ed060p262

Electrode Potentials:

Boettcher, S. W., Oener, S. Z., Lonergan, M. C., Surendranath, Y., Ardo, S., Brozek, C., & Kempler, P. A. (2021). Potentially Confusing: Potentials in Electrochemistry. ACS Energy Letters, 6(1), 261–266. https://doi.org/10.1021/acsenergylett.0c02443