Voltammetry Tips: CV and LSV + Demos!
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- čas přidán 1. 06. 2024
- This video shares tips on cyclic voltammetry (CV) and linear sweep voltammetry (LSV) as well as 2 experimental demonstrations.
It specifically educates on how to select a voltage scan rate and voltage step size for your LSV or CV experiment.
00:00 Cyclic Voltammetry (CV) vs Linear Sweep Voltammetry (LSV)
01:27 LSV of Diode Overview
02:52 CV of Batteries Overview
03:44 LSV of Battery Electrolytes Example
04:25 CV & LSV Equipment: Potentiostat
05:17 Introduction to Linear Voltage Ramp in Potentiostats
06:02 Tips: Selecting voltage step size + scan rate
06:25 Why it's important to select appropriate scan rate and step size
08:13 Summary of selecting appropriate settings
08:27 Experiment 1: LSV of Rectifier Diode - effect of scan rate + step size
11:53 Experiment 1: Results
12:27 How to select scan rate and step size for your experiment
13:26 Steps to set your scan rate and step size
14:34 Experiment 2: LSV of a Laser Diode
Special thanks to Electric Goddess and Admiral Instruments for making this video possible.
You can learn more about Electric Goddess at electricgoddess.co.
For more information on the Admiral Instruments Squidstat Plus potentiostat, visit www.admiralinstruments.com/
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Very good demonstration. Liked it! Thank you for the effort.
great work. Really impressive
These videos keep getting better and better, great work Jill! We have a new member in our research group and I'm going to go through your entire series to get them acquainted with electrochemical techniques!
Thank you! Happy to hear my videos are useful in trainings 😊🎉🙌
I appreciate your videos i like the way you explaining things
Very informative video.
Excellent video Jill! We look forward to following the adventures of "Squidward the potentiostat" in future videos :)
Thank you! Looking forward to Squidward’s help in many experiments 🧪🎉
great Video about CV!
Thanks! Very well explained!!
Thanks for watching! Glad you enjoyed it
So well explained!
Thank you!
I happened to run a lot of CV for my research. I also had to demonstrate DSC to our students for my TAship. It made me spot the analogy between these 2.
Very cool 😎, & you’re right! DSC is a thermal energy sweep & CV is a electrical energy sweep. In both the peaks/valleys indicate different energetic processes. I love that you see the parallels between the two! ⚡️🔥
Jill, can you fo a general video explaining the different types of trsting recommended for LIBs? For example Arbin cycling, ULPC, CV, EIS and when you would use each? Thanks!
Useful 👌🏻
Thanks for this well-explained video. I just wonder if you could make a video on how to analyse the LSV curve. I was told to draw 2 tangent lines to fine the onset potential at the intercept but not sure if this is the correct way to calculate it.
That’s one way of analyzing it. It really depends what your system is, what your hypothesis is, and what questions you’re trying to answer. To measure the onset potential of reactions, using the tangent-line drawing method (and matching it to what’s published in literature for those chemicals/materials) may be enough. If you are trying to answer more complex questions or discover new phenomena, you may need more experiments in addition to LSV and/or perform LSV on different systems related to the one you’re studying to draw more conclusions. Research and discovering new things is not easy! Best wishes!
Please make a video on how to calculate capacitance from CV.
Jill, thanks for this awesome video! I'm an EE student learning how to do CV. With the data from CV, how do I figure what's going on with material? Could you please provide some textbooks or material references on understanding CV results? For the diode example, you should had sweep the voltage pass 0.7v to see some cool stuff.
There’s a solid state physics book by Kittel that I have that explains pn junctions. I’m sure Wikipedia would give a good explanation on pn junctions as a place to start :)
Thanks, madam for your lovely explanation... could you please explain How I can calculate onset potential from CV data
Please can you make a video on measuring overpotential.. I'm currently working on electrodes for HER and I need to measure overpotential at a current density of 10mA/cm2 ...
Thanks Jill. it is a great video.
The question is I have done many CVs but never changed the step as my scan rate changed. how does it affect the data? Thanks is advance! :)
Thank you! Great question- the ability to change the step size is useful for very slow or very fast scan rates. I’m not sure the range of scan rates you were using, but it is possible the step size does not affect the data. I suppose if you were trying to resolve very subtle reactions/processes, a smaller step size may be able to resolve those better.
A 1.000 g sample of zinc metal is dissolved in 50 mL of 6 M HCl solution and diluted to the mark in a 250 mL volumetric flask. A 25.00 mL portion is transferred to a polarographic cell and oxygen is flushed out. A polarogram in the range 0 - 1 V (vs. the Hg-pool electrode) shows a wave at E1/2 = -0.65 V, id = 32.0 units of galvanometer deflection. A 5.00 mL portion of 5.00 x 10-4 M CdCi2 solution is added directly to the polarography cell which already contains the Zn solution, oxygen is again flushed out, and a second polarogram is taken. The wave shows the same E1/2 but the id is 77.5 units. Calculate the percent by weight of Cd impurity in the Zn metal. Note: Atomic weight of Cd is 112.4 g/mole.
Pleas any one help me for solution this problem
Great video! I guess I wish you were using a Pine potentiostat, but it's all good :), you did use a snipped from our knowledgebase so that's good :). I'm thinking about making a CV video as well, but it's on the back burner for now. Keep up the great work!
Thank you! Haha, this potentiostat works great! I’m about to run some tests on it today at work.
Are you suggesting we should collaborate on a video? 🤔😊 That could be fun!
@@AcrosstheNanoverse I haven't used the squid stat but I'm sure it's a solid potentiostat. And the software interface looks quite good.
I think a collaboration would be awesome! let me know if you wanna chat sometime and we could at least brainstorm. I could create a zoom meeting or something.
Hi . According to my understanding, the area of the closed curve of the iv plot represents the capacity of the battery،
Thank you for this thoroughly and calmly explained vid and good luck with your channel :)
I am planning to conduct electrofermentation whereby my growth medium undergoes electrolysis to produce hydrogen and oxygen, both of which are critical for the growth of my bacteria. However, the medium has to be optimized first so that it is stable under electrolysis, produces sufficient H2 and O2, and allows for good microbial growth.
I have read in some papers that LSV can be used to assess gas (H2 and O2) evolution without the need to actually capture and measure those gases (e.g. using GC/MS). This would be great for me, as gas measurement devices are not always available for us at the lab. However, I am not sure how LSV can actually help me assess gas evolution and what kind of indicators I need to look at in my LSV results to figure this out. So, can you please explain this to me, or at least point out further reading/vids that can help me understand this better? Any help would be highly appreciated.
You just need to know the potential at which you’d expect the reaction to take place. Once your voltage sweeps to that potential and you get a current response you can calculate the area under the peak as the amount of gas created (gas per coulomb of charge passed).
@@AcrosstheNanoverse The LSV peak is a very broad peak, like a duck curve, how the area under it would be measured?
Thanks for your informative video. I have a question. With a device that only has the LSV technique in its software, is it possible to have a CV test by defining two consecutive LSV tests? It should be true in theory, but is it true in practice?
Yes 👍
A very nice informative video mam, thank you. I have a query, what if we reverse the starting and ending potential like from 0.2 to -0.2, how it will impact the results and how we decide which starting and ending potentials to choose.
Thanks for the question! In a system like a diode it shouldn’t affect the results because there’s no hysteresis. For other systems like batteries, supercapacitors, etc. there may be different results if the range is reversed.
If there is no obvious current peak ---- how I can draw a graph relationship between the scan rate and current density from CV... data
Hi.
What is open circuit potential in settings section? Could you explain either elaborately or in layman's terms of why it was open circuit and not something else? How would the data be different in open circuit or other setting?
Good question! The open circuit potential (Voc) block I put in Experiment 2 was not essential to perform LSV. The software reads the Voc and then uses that as the reference point at which to assign 0 Volts. I didn’t have to use the block in that case, but decided to put it there as a mental note that the instrument needs a Voc measurement to identify the 0 Voltage point. The experiment worked just as well without the initial explicit Voc measurement at the beginning.
More generally, open circuit potential is the potential of the device or system without any current passing through it.
@@AcrosstheNanoverse Hi. Thank you for your reply. Continuing, do you mean that the magnitude of the data points would be almost same when run at Voc and Ref or the curve would be similiar in fashion?
Are these concepts of CV and LSV same for 3 electrode electrochemical testing, too?
Yes!
I made a TikTok to answer your question, but can’t post the link here.. strange
Thank you for your illustration. I want a video about LSV and CV in determination of corrosion rate
plz. I want to contact with you
How the three electrode system works?
Why the potential is always is vs. Li/Li+?
The way potential is measured is always compared to a reference potential. For lithium ion batteries, the reference potential is the potential at which Li+ gains or loses an electron as it undergoes redox reactions. There’s other types of reference potentials. I encourage you to Google NHE and SCE reference potentials for more fun 🤩
CVS can be taken only for half cell or full model?
Both 😊
@@AcrosstheNanoverse Thank you very much Mam, for the prompt response. Can You demo a single particle model and P2D model of lithium batteries.
The battery reaction order is random.
How to set the time and current parameters?
I’m not sure what you mean by battery reaction order. If you’re referring to increasing voltage and which reactions occur at each voltage, it is not a random order. It depends on the redox reaction potential. For CVs, you typically use a potentiostat like I have in the video to set parameters. I explain the settings in the video.
A rate law shows how the rate of a chemical reaction depends on reactant concentration. For a reaction such as aA → products, the rate law generally has the form rate = k[A]ⁿ, where k is a proportionality constant called the rate constant and n is the order of the reaction with respect to A. The value of n is not related to the reaction stoichiometry and must be determined by experiment.
The rate of a chemical reaction depends on reactant concentration and temperature and load and ...........
so the n (reaction order) is'nt random ?
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