Electrochemistry : characterizing the electrode-electrolyte

In summary, the conversation discusses the topic of electrode-electrolyte interface and the equivalent electrical circuit model for a metallic electrode in an aqueous solution with a DC current. The EDL capacitance for a metallic electrode is estimated to be around 20µF/cm² in solutions with millimolar to molar concentration of ions with AC current, but it is unclear if this value can be safely applied for deionized water and DC. The speaker also mentions working on streaming current and using deionized water as a fluid, and questions the impact of having no ions on the EDL.
  • #1
Florent
3
0
Hello guys (and gals),

I have mostly a background in Physics, but I've recently had to get some knowledge on electrochemistry, and more precisely on electrode-electrolyte interface.

From "Modern Electrochemistry 2A : Fundamentals of Electrodics" by Bockris I gathered that in the case of a metallic electrode plunged in an aqueous solution (with ultradilute concentration of inorganic ions) with a DC current, I can pretty much model it with a resistance and capacitor in parallel as an equivalent electrical circuit with the resistor being the interfacial resistance and the capacitor being the EDL capacitance.

From what I gathered, the capacitance of the EDL of a metallic electrode is generally estimated to be around 20µF/cm² in solutions with millimolar to molar concentration of ions with AC current. Can I safely take this value (or this order of magnitude) for my electrode in deionized water and DC or am I missing an important parameter that can change everything ?

Hope I'm making sense :p
Cheers !
 
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  • #2
μF or pF/cm2?
 
  • #3
µF/cm² for differential capacitance at least
 
Last edited:
  • #4
Florent said:
deionized water
??!
 
  • #5
Yes, I'm working on streaming current and on the data with deionized water as fluid
 
  • #6
EDL involves ions and water dipoles, no ions, much less pronounced EDL.

At least that would be my line of thinking.
 

1. What is electrochemistry?

Electrochemistry is the branch of chemistry that deals with the chemical changes caused by the movement of electrons. It involves the study of how electricity and chemical reactions are related.

2. What is an electrode?

An electrode is a conductor through which electricity enters or leaves an electrolytic cell. In electrochemistry, electrodes are used to facilitate the transfer of electrons during a chemical reaction.

3. What is an electrolyte?

An electrolyte is a substance that conducts electricity when dissolved in a solvent, such as water. In electrochemistry, electrolytes are used to carry ions between the electrode surfaces.

4. How do you characterize the electrode-electrolyte interface?

The electrode-electrolyte interface can be characterized using various techniques, such as electrochemical impedance spectroscopy, cyclic voltammetry, and chronoamperometry. These methods measure the electrical properties of the interface, such as conductivity and capacitance, to provide information about the electrode and electrolyte behavior.

5. Why is characterizing the electrode-electrolyte interface important?

Characterizing the electrode-electrolyte interface is important because it provides valuable information about the performance and efficiency of electrochemical systems. This information can be used to improve the design and functionality of batteries, fuel cells, and other electrochemical devices.

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