Donut Lab Episode 16: It's not a Lithium Battery, But There is Lithium in the Battery
Donut Lab is back with another piece of the puzzle we're all trying to solve.
In Episode 16 of I Donut Believe, Donut Lab has released the results of an independent elemental analysis carried out by Intertek in the UK.
And there's a surprise. There is lithium in the cell. There's sodium too. Just not very much of either.
For more Donut Lab news, visit our Donut Lab page.
The Test
Donut sent material from the same battery cell used in its earlier nail test to Intertek, after the cell had been dismantled, with around 0.5g of material from the anode, cathode and current collectors analysed.
The material was dissolved in nitric acid and tested using ICP-OES, a highly sensitive method capable of detecting elements in tiny concentrations. Intertek found 3.4 parts per million (ppm) of lithium and 632 ppm of sodium.
That's a very small amount of lithium. Donut says a conventional lithium-ion battery would contain lithium in the percentage range, rather than a few parts per million. We can get on board with that.
Read the Intertek Test report here.
So What Is It?
Donut CEO Marko Lehtimäki is still not revealing the battery chemistry. That's obviously deliberate. Donut says the test was commissioned to address the two biggest theories doing the rounds, namely that the battery is lithium-ion or sodium-ion.
Based on the Intertek results, Donut says neither is the answer. But here's the bit that caught our attention. If there's a small amount of lithium in there, where did it come from?
We don't know. And this test doesn't tell us.
The 3.4 ppm result is tiny, and by itself it doesn't tell us whether the lithium is part of the battery's chemistry, came from another component, or is simply present as a trace contaminant.
The same applies to the sodium. There's 632 ppm of it in the material Intertek tested, but that doesn't make the battery sodium-based. Donut isn't saying what the chemistry is, and this test wasn't designed to identify it.
Sodium is pretty much everywhere, so finding some isn't particularly shocking. Lithium is a little more intriguing, although 3.4 ppm is such a small amount that it tells us very little on its own.
Intertek was specifically asked to quantify lithium and sodium. It didn't identify the complete chemistry of the cell. So we've learned what isn't in there in meaningful quantities. But we still don't know what is.
The BCB Take
This is another useful, but frustrating, piece of evidence. The Intertek test appears to take a conventional lithium-ion or sodium-ion explanation off the table, at least for the material that was analysed
But we're not going to pretend this test has magically revealed the secret sauce. It hasn't. Donut still isn't telling us the chemistry, and that's the question we're ultimately interested in.
Episode 15 gave us 409.3 Wh/kg from VTT.
Episode 16 gives us an analysis showing almost no lithium and relatively little sodium.
Now we're left asking a really simple question. What the hell is it?
Roll on Episode 17.
Ride safe, folks.
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