Welcome back everyone!
I’m Jordan Giesige and this is The Limiting Factor.
Novonix has grabbed the imagination of the Tesla community lately and I’ve had several
requests to do a deep dive on the company.
I was originally going to do one video on Novonix, but after starting the deep dive,
it quickly became clear that it would take two videos.
In order to understand Novonix business model, we first need to understand Dry Particle Microgranulation,
or DPMG, in depth.
This video will cover DPMG, and the next video will cover the Novonix business model.
DPMG was discovered by Mark Obrovac’s team at Dalhousie University.
If Dalhousie University sounds familiar, that’s because this is also where Jeff Dahn’s lab
is.
For those who watched my video on Jeff Dahn, you’ll know that the Dahn Research Group
is Tesla’s research partner.
Mark Obrovac’s team, called the Obrovac Research Group is partnered with Novonix and
through that partnership, Novonix has access to the DPMG technology and has patented it.
Mark published a research paper titled “Engineered Particle Synthesis by Dry Particle Microgranulation”
on 13 May 2020 in Cell Reports Physical Science.
That research paper explained the benefits of DPMG, how it was discovered, and how it
works.
Let’s walk through the research paper step-by-step, starting with the title.
Engineered Particle Synthesis by Dry Particle Microgranulation simply means that Mark Obrovac
and his team have discovered a way to tightly control the way that micron sized particles
form, and they’re able to do this with a dry process.
It sounds mundane, but it has the potential to make the production of cathode and synthetic
anode profitable outside of China.
You’ll notice that I’ve been using the word discovered, rather than invented.
The machine that’s used for DPMG is widely commercially available and is referred to
as a mechanofusion machine.
Obrovac’s team has found a new way to use that machine.
Mechanofusion is the process of mixing and squeezing materials together until they fuse
to each other.
For the type of mechanofusion machine we’re referring to here, it refers to coating one
powder with another finer powder at the particle level.
The story begins for Mark Obrovac and his team in 2018.
In October of that year, they published a research paper titled “A High Quality Mechanofusion
Coating for Enhancing Lithium-ion Battery Cathode Material Performance.”
The research was led by Lituo Zheng and T.D. Hatchard and overseen by Obrovac.
We’ll refer to this as simply the 2018 coating paper.
For those of you who watched my ‘New information’ Battery Day video you’ll be familiar with
why they would want to apply a coating to the cathode: It can significantly increase
battery cycle life.
In this case, they were using aluminum oxide rather than the titanium oxide Jeff Dahn was
using in his Million Mile Battery paper.
One of the goals of this paper was to use mechanofusion to apply the aluminum oxide
coating in a more environmentally friendly and efficient way.
The current process for creating cathode materials and coating cathode materials is called co-precipitation,
which is inefficient and generates waste.
Co-precipitation is a process where a liquid containing dissolved solids is stirred in
solution at an exact ratio, temperature, concentration, and pH.
When the right conditions are met, the solution reacts to form solids that fall out of solution.
The solids that fall out of solution are a powdery particulate called precipitate.
This co-precipitation process is all done with a piece of equipment called a Continuously
Stirred Tank Reactor or CSTR, shown here.
A typical production facility using CSTR to produce anode materials uses 99,000 litres
of water per day to produce 6,500 kilograms of cathode material.
After precipitating out of solution the material must then be separated from the solution,
washed, and filtered.
This of course generates wastewater that needs to be treated.
Then, the precipitate is put through an energy intensive drying process involving fans and
heaters.
After the precipitate is dry, it’s ground down to the correct shape and size because
the CSTR method creates particles that are range of shapes and sizes.
The grinding process generates waste material that includes metals such as cobalt, manganese,
nickel, and aluminum.
These are all environmental hazards.
At this point in the process, the precipitate material is now what’s referred to as a
precursor.
The precursor is then heated with lithium carbonate or lithium hydroxide to form micron
sized crystals.
To the naked eye these crystals just look like black powder.
That black powder is the cathode material that goes into lithium-ion batteries.
Hold on a second, we haven’t even coated the cathode crystals yet.
Rather than walking through the process again and explaining how the CSTR process differs
for coatings, I’ve provided a snip of the coating process on screen, along with a citation
if you’d like to read further.
The citation I’m showing here was the same citation that Obrovac’s team used in the
2018 cathode coating research paper.
As you can see, the CSTR co-precipitation process is practically a Rube Goldberg machine
and an environmental minefield.
This is why Mark Obrovac’s team wanted to find a better way.
Let’s take a look at how the mechanofusion process would handle coating the cathode material
with Aluminum Oxide.
The mechanofusion machine shown here uses a drum, a press head, and a scraper.
To coat a material, particles of two different sizes are used.
In this case, the larger particles were probably 5-20 microns in diameter, and the smaller
particles were 13 nanometres in diameter.
The large particles to be coated were cathode material, and the small particles doing the
coating were aluminum oxide.
These large and small particles are both powders to the naked eye.
The powders are dumped into the drum and are referred to as feedstock.
In other words, the feedstock is the material that will be exposed to mechanofusion.
The drum is closed and the drum spins at 1000-5000 rpm, which just like the spin cycle on a washing
machine, creates centrifugal force.
The centrifugal force holds the feedstock against the drum as it’s squeezed through
the press head.
The scraper then removes the compressed particulate to ensure that it’s continuously mixed.
Mixing ensures that all the particles get their turn running through the press head
thousands of times, allowing the small and large particles to fuse.
The basic process is relatively straightforward.
Where the difficulty comes in is selecting the right speed and adjusting the distance
of the press head and scraper from the drum wall.
When all the variables are right, this is the result.
What you’re looking at are images of cathode coated with aluminum oxide at different levels
of magnification.
The ones on top were coated by hand grinding, and the ones on bottom were coated with mechanofusion.
In the top hand ground images, you can see that the cathode material is sugared with
aluminum oxide powders and it looks like fudge bliss balls.
In the bottom, mechanofusion images, you can see that the cathode almost looks like it
was dipped in white chocolate.
This is because the aluminum oxide fused with the surface of the cathode material, forming
a uniform coating, which is clearly better if your purpose is to protect the cathode.
This is where Obrovac’s team made a discovery.
Some of the aluminium oxide didn’t coat the cathode material.
Instead, it fused with other aluminum oxide particles to form smaller spheres of aluminum
oxide that contained no cathode material.
This was the lightbulb moment that brings us to the DPMG research paper.
For the DPMG research paper, the researchers used Lithium carbonate along with Nickel,
Manganese, and Cobalt oxides as the feedstock for the purpose of creating NMC cathode material.
The feedstock was then added to the mechanofusion machine with 50 micron zirconium oxide spheres.
These zirconium spheres were called template particles and were added to simulate the large
cathode particles in the 2018 coating paper.
The theory being that the large zirconium template particles would cause the feedstock
to fuse to itself and form spheres.
In other words to mimic what happened in the 2018 coating paper where the aluminum oxide
fused to itself to form spheres.
The ratio of template particles to feedstock was 10 to 1.
The end result was particulate that averaged 25 microns in diameter, which is shown here
contrasted against commercial NMC particles.
It’s worth noting that the DPMG particle shape can be modified and the DPMG particles
shown here have not yet been classified, whereas the commercial NMC particles have been classified.
Classification is the process of separating the particles to select for the specific particle
sizes.
Selecting particle size is necessary because part of the process of engineering a battery
cell involves selecting a particle size and shape that supports whatever combination of
energy density, cycle life, and power density that engineers are targeting.
The commercial particles would have originally contained large amounts of small particles
and these small particles would have been classified out of the mixture that we see
here.
For DPMG, the classification step is nearly eliminated and there is far less particulate
that needs to be classified out of the mixture.
Even better, that small particulate can be reused in the next DPMG batch.
The same can’t be said for the CSTR method, where the material that was classified out
is waste.
If you look closely at the image, you’ll notice that CSTR uses sulphate feedstock whereas
DPMG uses oxide feedstock.
Nickel is the main component of the cathode chemistries that most major battery manufacturers
use.
The nickel sulphate used in the CSTR method is Class 1 Nickel.
Class 1 Nickel is Nickel Sulphate with a purity greater than 99.8%.
The Nickel used in the DPMG method uses Class 2 Nickel, which is all the other forms of
Nickel that require less processing, such as Nickel Oxide or Ferronickel that contains
high amounts of Iron.
Nickel Oxide is significantly cheaper based on the reports I’ve read.
None of those reports provided an exact price difference between these materials.
This is because the price depends on the purity, quantity, and type of class 2 Nickel.
Regardless, Class 2 would be significantly cheaper than Class 1.
Most likely, more than 30% cheaper.
Finally, according to the research paper, the performance of the DPMG cathode material
was comparable to commercial CSTR material.
The researchers noted that they can vary the shape and structure of the NMC particles and
will continue to engineer and test these to see if they can improve the performance beyond
CSTR cathode materials.
DPMG can also be used to make graphite anode material.
As with the cathode, it’s best to start with the current process and work from there.
Graphite anode can be natural or synthetic.
Synthetic graphite is made by heating high carbon precursors, such as petroleum pitch,
to 3000 degrees Celsius.
The high heat causes the carbon precursor to crystalize into graphite.
After the graphite is formed, it goes through a process called spheroidization.
If you’ve ever had a rock tumbling machine, this is basically what happens during spheroidization.
It rounds and smooths the particles.
Natural Graphite is mined.
After it’s mined it needs to be ground down to the correct size by milling.
Milling results in around 50% of the material being lost as waste.
After it’s milled, it needs to be spheroidized as well.
At the end of the process, both natural and synthetic graphite are given a light coating
of carbon powder to make the surface smoother and reduce surface area.
Basically, this carbon powder fills in rough areas that might react and degrade more quickly.
Mark Obrovac’s team used natural graphite for the DPMG research paper.
The graphite behaved very differently than the cathode materials when subjected to the
mechanofusion.
At the start of the process, the graphite feedstock and zirconium template particles
were separate.
The graphite then began adhering to the template particles.
Finally, when the coating of graphite was thick enough it sloughed off to form spheres
of graphite.
The crystalline structure of these graphite spheres was very chaotic, and so, like synthetic
graphite, it was heated to 3000 degrees to increase the crystallinity.
A highly crystalline and orderly graphite structure is required for long cycle life
in batteries.
As part of this series on graphite materials, I’ll go into greater depth on the structure
and performance of anode material, but it’s beyond the scope of this video.
Much like the cathode material, any waste graphite can be reused in the process rather
than thrown away.
This gives the process and unprecedented 100% yield rate.
The performance of DPMG graphite material is seen here.
To help you make sense of this, I’ll provide some benchmark figures.
The theoretical energy capacity of graphite is 372 milliamp hours per gram.
The real world initial energy capacity of natural graphite is 350-360 milliamp hours
per gram.
After this first cycle, when the SEI layer forms, only 90-92% of that is usually left,
which is called first cycle efficiency.
This leaves 320-330 milliamp hours per gram of useable energy capacity.
The DPMG graphite appears to have an initial capacity of 330 milliamp hours per gram, which
drops to 280 after the first cycle, and levels off at 270 milliamp hours per gram.
This isn’t a great showing, but the researchers advise that this was caused by the zirconium
template particles creating impurities in the graphite.
They go on to say that they’re working on eliminating these impurities and will discuss
it in a future research paper.
I’m confident they’ll solve this problem.
The morphology and cycle life of the graphite particles produced by the DPMG process was
excellent.
Morphology refers the shape and structure of the particles.
The DPMG particles had an onion like morphology.
That is, they were spheroidal and layered, and had few exposed edges.
Spheroidal particles are desirable because they allow better access to the electrolyte
than flat particles.
Exposed edges reduce the integrity of the graphite material just like the frayed edges
of a piece of fabric.
This means the onion morphology which has few exposed edges, should lead to longer battery
life.
The DPMG research paper closes by saying that the researchers are investigating optimising
the process so it can be scaled up.
That is, they’re working on lowering the processing time, increasing the feedstock
to Template Particle ratio, and determining the impact of larger-scale equipment on processing
efficiency.
This sentence has large implications because even small changes to any of these variables
creates drastic differences in cost.
I ran calculations based on the capacity of the machines available and the processing
times laid out in the DPMG research paper and I was still left with a variation of an
order of magnitude difference between my highest and lowest cost estimates.
With that said, Chris has confirmed with me that with scaled production, Novonix is targeting
a cost of less than $5000/tonne for PUREgraphite, which indicates that Novonix may have already
solved the engineering cost challenges.
$5,000 per tonne is significantly cheaper than the typical $8,000 per tonne production
cost for synthetic anode.
If Novonix can hit the $5,000 per tonne cost target or even $8,000 per tonne the future
is bright for Novonix and DPMG.
If I were to rate the research paper itself, I’d give it a 10 out of 10.
That’s 5 out of 5 points each for being both useful and interesting.
By useful, I mean useful for industry and consumers.
DPMG could be used for far more than just battery materials and could be used across
industries.
In terms of interesting, any story that involves an elegant solution hiding in plain sight
with a clear eureka moment and clear explanation of the underlying mechanisms always captivates
me.
The next video is on the Novonix business model.
We’ll get further into where Novonix is headed as a company, their products and market
potential, and how these products might help battery producers de-risk their business models.
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