Welcome back everyone, I'm Jordan Geisigee and this is The Limiting Factor. A little over a year ago, I shared the specs for the 4680 battery cell analyzed by Shirley Mungslab at UC San Diego. However, there was one more test to be carried out that took a few more months to line up. X-ray diffraction analysis of the anode. The result of that test was that it confirmed that the 4680 cell that was tested uses synthetic graphite for the anode. The question is, what does that mean and what are the implications for Tesla? To answer that, today I'm going to walk you through the analysis done by UC San Diego, the differences between synthetic and natural graphite anodes, why Tesla may have chosen synthetic graphite and what that choice could mean for Tesla's supply chain.
Before we begin, a special thanks to my Patreon supporters, YouTube members and Twitter subscribers as well as RebellionAir.com. They specialize in helping investors manage concentrated positions. RebellionAir can help with covered calls, risk management and creating a money master plan from your financial first principles. Additionally, thanks to Shirley Mung of UC San Diego for organizing funding for the 4680 analysis as the Zabel Endowed Chair in Energy Technologies in Jacob's School of Engineering. And thanks to Y-ConGlee for performing the analysis, assembling the slides and answering my questions.
To kick things off, I first need to clarify the terminology I'll be using. There are two types of graphite, synthetic and natural. I'll explain the difference between the two later in the video, but for now, in short, synthetic graphite is manufactured, whereas natural graphite is formed by geologic processes. Bear in mind that synthetic graphite can also be called artificial graphite, and I'll be using those terms interchangeably throughout the video. Whether graphite is synthetic or natural, it can be used in everything from lubricants to coatings to batteries. The graphite that's used in batteries is further processed into a specially product that's used as the anode or negative electrode of battery cells. That is, natural and synthetic graphite refer to the raw materials, and those raw materials are used to produce finished products, which, for this video, I'm going to refer to as natural and synthetic anode.
With that understanding in place, let's take a look at the analysis from Shirley Mung's team at UC San Diego. Y Kong Lee provided me with two pieces of evidence that the 4680 is using artificial graphite. The first is this slide which shows a scanning electron microscope, or SEM, image of a reference artificial graphite sample versus the graphite used in the 4680. And based on visual cues, the 4680 appears to use artificial graphite. What are the visual cues we should be looking for here? In a word, porosity. One screen is a comparison between a natural graphite particle and an artificial graphite particle. The porosity of natural and artificial graphite can vary somewhat depending on how it was manufactured, but in general what we see here is representative of what's typical. As you can see, the artificial graphite contains fewer and smaller voids than the natural graphite particle. However, when graphite particles are coated to the electrode foil and a production battery cell, the coating process involves crushing the graphite onto the electrode foil in a process called calendaring. That calendaring process can also create porosity.
The comparison images I showed of natural and artificial graphite have a rounded shape, and therefore don't appear to have gone through a calendaring process. So although they do a good job of illustrating how porosity can vary between natural and artificial graphite that's in a standalone powder, they don't serve as a good benchmark for the graphite from a production battery cell. That's as opposed to the graphite samples in the slide from UC San Diego, which are both from battery cells that have been through the full production process. That's evidenced by the flattened top layer. If we look at the porosity of the artificial graphite reference versus the 4680 graphite, we can see that the porosity is relatively similar. That is, at first glance, the SEM images appear to be similar materials, which gives us one point of verification that the 4680 is using artificial graphite.
But what about a stronger verification signal? UC San Diego also provided this X-ray diffraction analysis. X-ray diffraction, or XRD, basically means shining X-rays through a material. The way that the X-rays bounce through that material gives a fingerprint of that material. Artificial and natural graphite have distinct XRD fingerprints. So if you compare an unknown graphite sample to the known fingerprints, it allows you to confirm whether you're looking at natural or artificial graphite. On the far right of the slide is a reference plot that provides a key for what those fingerprints look like. However, it uses a lot of jargon and acronyms that I can boil down into plain English. With that in mind, I'll remove the reference plot to simplify the page, leaving just the analysis results.
For this analysis, Ycong Lee used two benchmarks for double confirmation. The sample in black is the 4680 graphite. The sample in red was from an LG 2170 battery cell that's known to use artificial graphite. And the sample in blue was an artificial graphite reference material. To confirm the XRD fingerprints match, the key part of the XRD plot to look at is the box highlighted in light green. That's because this is the area of the plot where natural and artificial graphite would differ in their XRD fingerprints. To provide greater clarity, Ycong provided an expanded view of the area highlighted in green to the right of the main plot.
As you can see, although the height of the black, red, and blue lines differ slightly, their shape is fundamentally the same. Two separate peaks with a shorter peak on the left and a taller peak on the right. This means the fingerprints match and they're all the same material, artificial graphite. So we can say with a high level of confidence that the 4680 is using artificial graphite for the anode. Before we move on, let's cover two notes on the UC San Diego XRD analysis. First, Ycong Lee used several milligrams of powder. That means the analysis looked at tens of thousands of particles.
So there's no chance that any potential natural graphite was missed on account of it not being included in the sample. Second, however, with that said, the XRD machine did have a detection limit of 5%. So there is a small chance that there was some natural graphite in the sample, but it wouldn't change the main conclusion, which is that the graphite used in the generation 14680 cell is predominantly synthetic rather than a blend containing any significant amount of natural graphite. Moving along, the next question is, what are the differences between synthetic and natural graphite and why does it matter?
To understand that, let's start with a quick comparison of the manufacturing processes for synthetic versus natural graphite. As I said earlier, natural graphite is formed through geologic processes. Carbon-rich material is heated and compressed deep in the earth over millions of years, which causes it to form into thousands of layers of carbon sheets, also known as graphene. That is, graphite is just a carbon-based crystal made of thousands of layers of graphene. Artificial graphite is also produced using carbon-rich material, such as needle coke from coal or oil.
And instead of being heated and compressed deep in the earth for millions of years, it's heated in a furnace to over 2,500 degrees Celsius for hours or even days to graphitize the carbon material. If the raw graphite in hand, whether it's natural or artificial, it then undergoes processing steps to form the graphite into particles of the right purity, size, shape, and surface texture. After those steps are complete, the graphite becomes what I'm referring to in this video as natural anode and synthetic anode, which is a finished product rather than a raw material.
The next question is how do the cost, performance, and environmental profiles of natural and synthetic anode compare? First, with regards to cost, in the past four years, on average, the price of synthetic anode has typically cost about 15-25% more than natural graphite. That's because for natural graphite, mother nature did most of the work, whereas heating the synthetic graphite feedstock to thousands of degrees Celsius for hours or days uses about 13-14 megawatt hours to produce each ton of graphite. Second, with regards to performance, when I did a meta-analysis of natural versus synthetic anode a few years ago, the conclusion I came to was that performance is heavily product-dependent.
But that overall, natural anode offers great performance at low cost, whereas synthetic anode offers excellent performance at high cost. What do I mean by performance? Synthetic offers higher cycle life, thermal stability, and better charge and discharge rates. Natural anode can have an edge in energy density, but it's typically only a 1-2% advantage. The biggest advantage that natural graphite has over synthetic is that it tends to have much lower GWP, or global warming potential by around 75% less. That raises the question. If Tesla's mission statement is to accelerate the world's transition to sustainable energy, presumably to reduce the impacts of climate change due to CO2 emissions, why would they use any synthetic graphite that's made from fossil fuel waste and has higher CO2 emissions than natural graphite? Let's tackle that question from two levels. First, at a broader level to provide some perspective, and then from a technical and supply chain standpoint.
This image is from Tesla's 2022 impact report. It shows that it takes less than two years worth of driving before the total emissions from an EV fall below that of a comparable internal combustion vehicle. That's because even though many EVs use synthetic anodes made from fossil fuel by products in CO2 intensive processes, those are one-off emissions from manufacturing. Internal combustion vehicles use hundreds of gallons or thousands of liters of fuel per year, every year throughout their life. So even if EVs release about 50% more CO2 during the manufacturing process, their fuel, so to speak, is electrons and not a carbon-based liquid that has to be burned to move the vehicle. So the ongoing emissions are about 80% less on a yearly basis. Yes, a portion of the grid does generate energy from fossil fuels, but the electrical grid in the US and Europe are now primarily powered by natural gas, nuclear, and renewable energy sources which produce far less CO2 emissions and pollutants than coal or gasoline. With all that said, the fact that the lifetime CO2 emissions of EVs is lower than internal combustion vehicles still doesn't fully explain the logic of why Tesla would use synthetic over natural graphite, which at face value would appear to reduce total emissions even further. So what's going on here? In my view, that face value assessment fails to take into account technical and supply chain variables. Let's take a look.
Bear in mind that this is my best guess at Tesla's graphite anode strategy from what we know at this point in time. That strategy may evolve over time, and they might use different anode material or blends of anode material in different continents, or even different lines at the same facility servicing different products. The first reason why Tesla's using synthetic anode is that, overall, it has better performance or the performance characteristics they're looking for. As I said earlier, albeit at a higher cost, synthetic is able to offer higher cycle life, better thermal stability, and better charge and discharge rates. Tesla's certainly run the cost benefit analysis, and at least for the time being, they view higher cycle life and faster charge rates as a priority. The second reason could be scalability. Tesla has ambitious growth plans, and when it comes to batteries, they tend to work with the largest material suppliers in the world that have the greatest ability to scale. The fossil fuel industry is roughly two orders of magnitude, or 100 times larger, than the battery industry. Although it is true that needle coke sourced from coal and oil to make synthetic anode is a highly specialized chemical, it may be faster, easier, and more reliable to get oil refiners to expand needle coke production than it is to wait for natural graphite mines to gain financing and regulatory approval to build their projects, which can take 7-10 years. Building on the scalability point, the third reason Tesla's using synthetic graphite may be that they're moving as fast as possible to build at least one terawatt hour of vertically integrated battery manufacturing capacity in the US. In my view, there are three reasons for that. First, China has a near monopoly on the global supply of battery materials, particularly graphite anode production, which is a supply chain risk for Tesla. Second, it's an opportunity to reduce the manufacturing related CO2 emissions of their vehicles. And third, it'll reduce logistics costs and CO2 emissions from transport. Let's take a look at each.
So what's the path of least resistance for Tesla to build a vertically integrated graphite supply chain in the US? Tesla's Austin Gigafactory, which will be home to most of their North American battery cell production, is in the heart of Texas. And Texas is of course the heart of the fossil fuel industry in the United States, with ample refining capacity and expertise nearby on the Gulf of Mexico. In fact, on the Texas-Louisiana border is Philips 66 Lake Charles Coke production plant. Outside of China, Philips 66 is the leading worldwide producer of needle coke used to produce synthetic anode. And Lake Charles is only one of two global locations where Philips produces that needle coke. What all this means is that the precursor materials that Tesla would need to create a vertically integrated synthetic graphite anode supply chain are already there on the Gulf Coast, near the Austin Gigafactory.
Why would Tesla use natural graphite if there's a ready-made supply chain on their doorstep that at least for this decade potentially has the ability to scale to huge volumes of raw material relatively quickly? Furthermore, vertically integrating synthetic anode production in and around Texas would also give Tesla a chance to address the two primary drawbacks of synthetic anode, which are that it has a large CO2 footprint and that it's typically more expensive than natural anode. As I said earlier, needle coke has to be heated to 2500 degrees Celsius to graphitize the carbon, which is energy intensive. Since most synthetic graphite is produced in China, the huge amount of power that's required is provided mainly by coal-fired power plants, which in turn release huge amounts of CO2.
The grid in the US is much cleaner, meaning that synthetic anode produced in the US would have lower CO2 emissions. Furthermore, Tesla could provide their own solar panels and battery storage to drive down electricity costs and reduce the CO2 emissions at the particle refinement stage, which is also energy intensive. Beyond that, a secondary source of emissions for Chinese synthetic graphite is transport. As this image from Novonic shows, some of the needle coke that's used to produce synthetic anode in China can come from as far away as Philip's 66 Humber Plant in the United Kingdom. Then when it arrives in China, it bounces around to different production plants to convert it to a finished anode product before being shipped to the United States to go into a battery cell.
This is almost 25,000 miles of travel and corresponding CO2 emissions. If Tesla decided to vertically integrate anode production in Texas, they could set up an anode refinery in Corpus Christi near their lithium refinery. Ship in synthetic graphite from Philip's 66, in Lake Charles, for refinement into synthetic anode and then send the finished synthetic anode to Austin to go into batteries. Of course, they could buy that anode from a company like Novonics if they decided not to vertically integrate or if they wanted to diversify their supply chain. Novonics is pursuing a similar vertical integration strategy in the US and their assessment shows that by using hydropower and reducing transport distances, that they can achieve a 60% reduction in global warming potential for their synthetic anode versus a comparable synthetic anode from China and a 30% reduction in global warming potential compared to a natural anode from China.
It looks like their calculation may have been different from benchmark minerals calculation but even in a worst case scenario, synthetic anode produced in the US from clean energy would be roughly on par with natural anode from China. Finally, on cost. As I showed earlier, synthetic anode typically costs significantly more than natural anode. However, that cost advantage is narrowing. The price premium for high-end synthetic anode produced in China is now only about 7%. I don't know if that trend will hold but it does show that the price difference is surmountable. As a side note, thanks to Lars Lee's doll of Ristad Energy for supplying this graph for the video. If you're on X, give them a follow.
If Tesla vertically integrated synthetic anode production in the US to reduce shipping costs, cut out the middleman costs which can easily run 20% and provided their own cheap solar and batteries at production costs, they might actually be able to reduce the cost of their synthetic anode to below the cost of natural anode from China while ending up with a higher performance product. Again, bear in mind, this is all informed speculation on my part. The intent here is to provide a framework for thinking about why Tesla chose synthetic anode for the 4680, how the supply chain could evolve over time and why that matters.
Before we move on to the summary, let's cover two points that might show up in the comments. Some people might point out that, as I showed in my previous videos, Tesla currently isn't using any silicon in the 4680, but that they intend to use much more in the future. Why is graphite anode supply a concern to Tesla if they're moving towards higher silicon anodes in the future? It's because the silicon in the anode will be the salt in the salad and graphite is needed to buffer the expansion and contraction of the silicon. Because of that, I don't see Tesla using any more than 20% silicon by weight in the anode of their battery cells this decade. That means by far the bulk of the anode will still be graphite, so the use of silicon will reduce the amount of graphite they'll need, but over time they'll still need hundreds of thousands of tons of graphite per year.
Second, what does the fact that Tesla is using synthetic anode mean for Novonics and TALGA, which I did videos on a few years ago? In both cases, in my view, it doesn't impact them positively or negatively. That's because what matters for those companies to succeed is that they can hit commercial scale and that their products offer good performance for their price. If they can do that, they'll sell every kilogram of anode material they can produce, because for the rest of the decade there's huge demand for graphite anode.
In summary, the best available analysis we have so far indicates that the 4680 battery cell is using synthetic graphite and no natural graphite. This result may be surprising because natural graphite seems like a more environmentally friendly option. However, looking at it through a more strategic lens, even though synthetic graphite has higher CO2 emissions per unit of material produced, there are other factors that balance that out. First, synthetic graphite tends to be able to achieve higher cycle life than natural graphite and could make each battery sell that Tesla produces last longer. That means each vehicle will be on the road longer, spreading the CO2 emissions from manufacturing over more years and therefore reducing the average CO2 emissions per year.
Second, if Tesla localized the supply chain, that could reduce the global warming potential of synthetic graphite to the point where it's at parity or even lower than natural graphite. Third, if Tesla finds they can scale and vertically integrate synthetic graphite production in the US more quickly than natural graphite, that means more EVs on the road reducing global CO2 emissions. Yes, those vehicles might have higher CO2 emissions in the manufacturing stage than vehicles produced using natural graphite, but due to the cumulative benefits over time, it's obviously better to have those vehicles on the road than internal combustion vehicles.
And by a large margin, the only remaining question I have is how a battery strategy based on synthetic anode will work out in the long run because the world is moving away from fossil fuels. That may mean that the supply of needle coke as a fossil fuel byproduct will become more scarce over time. With that said, interestingly, in my research for this video, I did come across ways to create needle coke that are potentially more environmentally friendly, such as liquefying coal to turn it into coal tar. If you'd like me to make a video on that, let me know in the comments below.
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