Surface Analysis Methods for Electrodes

Each of these methods provides specific information about the surface properties of materials, which is crucial for electrode studies.

1. BET (Brunauer-Emmett-Teller)

• Primary information: Specific surface area (m²/g)
• Theory basis: Multi-layer gas adsorption on solid surfaces
• Application in electrodes: Determines total accessible surface area for electrochemical reactions
• Key insight: Higher surface area generally correlates with better electrode performance due to increased active sites

2. Multi-point BET

• Primary information: More accurate surface area determination
• Advantage over single-point: Uses multiple relative pressure points (P/P₀) for higher accuracy
• Application: Standard approach for rigorous surface area analysis
• Interpretation: Provides BET constant (C) which indicates adsorption energy strength

3. BET Fitting Plot

• Primary information: Linearity assessment of BET equation applicability
• What to look for: Linear plot with positive y-intercept in the relative pressure range of 0.05-0.35
• Significance: Validates if the BET model is appropriate for your material
• Warning sign: Poor linear fit suggests the BET model may not be suitable

4. Total Pore Volume

• Primary information: Total volume of pores per gram of material
• Measurement method: Calculated from amount of vapor adsorbed at relative pressure close to unity
• Electrode relevance: Indicates capacity for electrolyte uptake and ion storage
• Limitation: Doesn't provide information about pore size distribution

5. Langmuir

• Primary information: Surface area based on monolayer adsorption
• Difference from BET: Assumes only single layer adsorption
• Best for: Materials with predominantly micropores (
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This information is quite general. Could you please recommend a specific study or paper?

Can you provide me a specific title?

I will recommend a lot of research articles, chapters, even books.

The BET calculation provides the specific surface area of a material (m^2/g). This is important for any work that relies on surface interactions (adsorption of contaminants, electrodes, catalysis, etc.). A larger surface area means a larger number of sites for interactions to take place. This is of course separate from surface functionality and surface homogeneity which is also important in most of these interactions. When running a sample, if you are in a hurry, you can often run a 3 point BET just to check that your surface area is where you expect it to be. This is more typical of industries that are just doing quality control. I typically run a whole isotherm adsorption and desorption of about 132 points. While not strictly necessary for many applications it gives a greater degree of accuracy and precision.

The total Pore volume is a way of looking at the accessible surface area and is important to combine with the T-plot calculation which gives you the microporosity and mesoporosity of the sample. These are important as they effect how your electrolyte will interact with your electrode. If the pores are too small it becomes more difficult for the ions to intercalate into the electrode. You might think of it as the difference between a set of parking spots with a wide road that arrives at them and a set with a single lane road. The pore size distribution is important to the kinetics of this interaction.

Langmuir is less useful in surface area applications and is typically not reported.

BJH while still useful is typically less used than DFT and NLDFT.

Here is a link to a talk Pearl Kim has given on your topic of interest:

https://micromeritics.com/resources/characterizing-advanced-battery-anodes-with-gas-adsorption-bet-surface-area-and-dft-surface-energy/