1
$\begingroup$

I want to conduct in-situ XRD of a cathode in my battery using this coin cell with a kapton viewing window. I assume this cell configuration is the best I can find for my purpose, and that I can't easily make a better cell. However, the viewing window isn't super helpful if I still need to use a stainless steel current collector, as I have previously.

Thus it seems I have two options:

  1. Make a donut-shaped anode and separator, and XRD through the hole in the donut to hit the cathode. However, I worry that the cathode may not fully lithiate in the center, because it is not as close to in contact with my anode.
  2. Find a current collector which is transparent to XRD. Does anyone have a suggestion for such a current collector?
$\endgroup$
  • $\begingroup$ The link to the cell casing suggests using a graphite current collector if performing XRD. $\endgroup$ – AndyW Oct 31 '17 at 17:40
  • $\begingroup$ Yes, but that suggests it for the donut like cell setup, if I understand correctly. $\endgroup$ – User2341 Oct 31 '17 at 17:46
  • $\begingroup$ Ah, possibly. Based on the structure image on that page, I'd assumed you were simply trying to replace the Al/Cu ring, but I see that might not be the case. What is the structure of your cell, and which bit are you trying to study with XRD? $\endgroup$ – AndyW Nov 1 '17 at 8:44
  • 1
    $\begingroup$ I am trying to replace the al/cu ring with a full disc which can distribute current to the entire cathode. This is because I want to make sure that the section I am observing is truly fully lithiated. $\endgroup$ – User2341 Nov 1 '17 at 17:18
  • $\begingroup$ In that case I'd think you would be ok with a graphite full disc. They suggest you coat the electrode onto the graphite, which doesn't sound right for a donut structure anyway. HOPG does have an XRD pattern, but it's a simple one that you should be able to overlook if it's present in your data. $\endgroup$ – AndyW Nov 2 '17 at 8:57
1
$\begingroup$

You might have success with amorphous carbon sheets[1]. It's not cheap, but it's effective. It's the material used in the windows of the AMPIX cell[2] developed at Argonne. It does react at low potentials, though, so might not work for anode studies.

Have you considered aluminum? It's crystalline, but cubic so there aren't very many peaks to worry about.

This paper[3] might be helpful as you work on your experiments. You're right to think that not having a current collector for part of the electrode would affect the degree of lithiation; it's actually worse than that. Those kapton window cells are convenient, but always put an asterisk next to your results.

I'm doing a fair amount of in-situ characterization for my PhD. If you can share more about you goals, I'd be happy to chime in.

[1] http://www.htw-germany.com/products.php5?lang=en&nav0=3&nav1=6

[2] http://scripts.iucr.org/cgi-bin/paper?S0021889812042720

[3] https://pubs.acs.org/doi/abs/10.1021/acs.jpclett.5b00891

$\endgroup$
  • $\begingroup$ This is actually really interesting. The AMPHIX cell looks great, and even like something I could build. However, I require that my electrodes be able to have some form of current collector, rather than begin free standing. Do you have any experience when it comes to XRD that's note free standing? $\endgroup$ – User2341 May 2 '18 at 1:38
  • $\begingroup$ A little, though not in the way you're trying to do it. I've used pyrolized graphite sheets but above 4.5V it will start intercolating PF5^- ions. $\endgroup$ – Mark Wolfman May 5 '18 at 2:02
  • $\begingroup$ I'm not sure I fully follow but it seems like theres not a great way to do any insitu xrd without the electrode being free standing? $\endgroup$ – User2341 May 6 '18 at 23:06
  • $\begingroup$ What energy X-rays are you hoping to use? $\endgroup$ – Mark Wolfman May 6 '18 at 23:31

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.