Anode Technology
We’ve looked at the Electrode technology where Tesla’s innovation to use a Dry Battery Electrode manufacturing process will give a major part of the battery puzzle it’s order of magnitude improvement.
For Lithium we looked at the technology from Lilac Solutions which will do the same for this part of the battery supply chain.
For Cathodes, an order of magnitude step change is not so much on a breakthrough trajectory, but what is happening is the various components that make up the flow chart to getting a resource out of the ground & processed are being simultaneously focused on. Exploration, AI analysis looking for geochemical markers (Kobold Metals), autonomous mining equipment, re-working older mines by digging deeper, focusing on ESG criteria, designing processing plants which extract more than one valuable element from each tonne of ore & focusing on a circular economy for minerals through recycling (Redwood Materials).
Circling back now to an older representation of a Tesla battery Cell roll which shows the individual components that make up the Lithium battery. The Electrolyte, Cathode & Anode have been the focus of major R&D efforts to attempt to reduce or substitute material to lower cost by trying different approaches such as for the cathode tweaking battery chemistry – ie NMC 5:3:2/6:2:2/8:1:1 etc, NMA, LFP etc
Looking at the component recovery breakdown during the recycling process you get a good idea of the total amount of each material which makes up a typical Lithium battery.
If you recall the four generations of Lithium battery identified in The Limiting Factor interview with Professor Shirley Meng.
Gen 0 – Cathode TiS2 / Anode Thick Lithium Metal
Gen 1 (current tech) – Cathode LCO, LFP, NMC, NMA / Anode Carbon (graphite)
Gen 2 – Cathode NMC, NMA / Anode Si-Composite Anode
Gen 3 – Cathode Hi-Nickel NMC, Sulfur / Anode Ultra-Thin Lithium Metal
Anode (Graphite, Graphite/Silicon composite, Silicon, Li-Metal)
Typical Active material applied to copper foil
I want to tell them we absolutely have Moore’s law in the expansion of the number of sales every two years. So graphite will be here with us for a long time. Why? Because the world needs a few tens of terrawatt hours. I mean we barely hit a few a couple hundred gigawatt right so you’re looking at 100 expansions in the future years so we will you know a lot of the materials will be
utilized because the batteries will be everywhere. We’re electrifying everything you know
The Limiting Factor interview of Professor Shirley Meng: The Future of the Anode (C, Si, Li)
The chemistry for the Anode side of Lithium batteries is Graphite as the predominant material used. Current numbers cited (see below) are 96% of the Lithium battery utilising graphite as the anode with this expected to grow to 10% by 2030. There will be other, likely more up to date sources out there, but the amount cited is around 1.2 kg of graphite per kWh. https://bit.ly/3EP05zh
Q1 2021 | BENCHMARK QUARTERLY – ISSUE 25
How is graphite for batteries made?
Graphite for batteries currently accounts to only 5 percent of the global demand. Graphite comes in two forms: natural graphite from mines and synthetic graphite from petroleum coke. Both types are used for Li-ion anode material with 55 percent gravitating towards synthetic and the balance to natural graphite.
Where the main current challenges for the Cathode component of Lithium batteries is predominantly about ramping the resource (exploration/mining/refining) supply chain, for the anode component graphite is able to be produced synthetically from hydrocarbons as well as mined, the main area of focus appears to be less on the supply chain & more on technologies to ramp & improve manufacturing processes. Noting that although graphite is the current main Anode material, Silicon is able to hold up to 10 times more Lithium, however the Silicon Particles grow in size up to 300% which causes a number of other challenges which need to be resolved.
Gen 1 (current technology) – Cathode LCO, LFP, NMC, NMA / Anode Carbon (graphite)
Cathode process improvements
For one example of where Gen 1 NMC/NMA cathode & graphite (carbon) anode solutions are at, please take a look at a July 30, ShareCafe ‘hidden gems’ webinar which included a number of leading market solution providers who focus on shoring up the lithium ion battery raw material supply chain. This included Benchmark Minerals who are a leading subject matter expert on critical minerals which are required for ramping lithium batteries, including tracking the number of battery megafactories in various stages of development around the world.
Novonix are both an R&D company focused on developing & improving battery technology solutions. This includes battery material refining, battery testing technologies, battery materials – cathode processing technology such as dry synthesis to reduce the cost & improve ESG profile, anode processing technologies (synthetic graphite/HPA coating), battery cell & pack production.
Novonix have developed a DPMG or Dry-Particle Microgranulation dry synthesis technology to produce the Cathode precursor materials – essentially mixing the Nickel, Cobalt, Magnesium Oxides that go into the Cathode of a Lithium battery. Novonix DPMG process utilizes what appears to be an industry standard centrifuge which, via mechanical means, forces powdered metal oxide particles (or graphite/HPA for the anode) to fuse together.
A potential advantage DPMG offers is similar to Tesla’s DBE Dry Battery Electrolyte process in the reduction of Capex & Opex with the elimination of complex equipment, high use of toxic chemicals & solvents as both processes are ‘dry’, so also reduction in energy inputs/carbon dioxide outputs by getting rid of the requirement for large drying lines. The goal for Novonix with this technology development path is to produce a cost effective single crystal cathode material – A combined Nickel, Cobalt, Manganese crystal which could then be used as the key ingredient in Tesla’s Dry Battery Electrode manufacturing process.
Novonix (ASX:NVX) patents single crystal cathode tech
From the Porsche graphic, pathways to reduction of battery costs are relatively well understood. Cell optimization through material engineering, Production process optimization through dry pre-cursor (single crystal DPMG) & dry battery electrolyte processes which leads to faster production, finally learning curve, geographically locating production facilities (transport costs etc) & economies of scale.
CSTR Continuous Stirred Tank Reactor Vs DPMG process
The Limiting Factor has a Youtube on Novonix DPMG technology
Novonix DPMG – Dry Particle Microgranulation (Deep Dive)
Anode process improvements
A good explanation of what happens to the Anode material during the first cycle courtesy of Iggy Tan from Altech Chemicals during a recent presentation.
50:35 New World Metals Conference – Session 2
What people don’t understand is that about 10% of the lithium stays on the anode and it becomes inactive to the battery…well what’s happening is that the first cycle loss is due to the lithium being absorbed around the graphite particles – it forms an SEI layer … it becomes inactive…during the life of the battery the SEI layer cracks and it exposes more sites that lithium gets absorbed on… the other issue is also hydrofluoric ions which is in the electrolytes break down the SEI layer & exposes more sites & more lithium is absorbed and that’s why you see a degradation of lithium in the performance of the battery.
7:00 The Novonix Battery Materials Opportunity
High Purity Alumina (HPA) is a premium industrial material valued for its chemical stability; high melting point; friction and high wear-resistance; thermal and electrical insulating ability; and its ability to withstand extreme temperatures. It’s uses include synthetic sapphire wafers used in LEDs, separator coatings in Lithium Ion Batteries, Micro-Chip Semi Conductors, High Performance Catalysts, Purity grinding media & High Performance ceramics.
Graphite is the predominant anode technology in current lithium batteries. Synthetic Graphite is manufactured by high temperature (>4000°C) treatment of amorphous carbon materials such as petrochemicals, coke, coal tar pitch, acetylene.
Novonix synthetic Graphite processing solution is aimed at increasing the life of lithium batteries by coating or fusing High Purity Alumina (HPA) around the graphite particle.
Novonix along with other companies have successfully coated Graphite with HPA at the nano scale which has shown in laboratory test conditions to reduce first cycle capacity loss in lithium batteries & as a result offers to increase battery life (remember the Tesla Million Mile battery). Novonix uses the DPMG process to achieve this via mechanical means.
Novonix already have a first mover advantage in the US as they are the only qualified US-based supplier of synthetic graphite anode material. According to The Limiting Factor, qualifying Cathode material takes 5 months, however qualifying anode material can take up to 18 months.
Altech have also produced the following youtube video showing the anode material which they plan on manufacturing.
Gen 2 – Sliicon/Graphite composite Anode
Circling back again to the graphic which shows the iterations in Lithium Battery technologies & we saw :
Gen 1 (current tech) – Cathode LCO, LFP, NMC, NMA / Anode Carbon (graphite)
Gen 2 – Cathode NMC, NMA / Anode Si-Composite Anode
However current technology, as with the coating of the graphite with HPA is being developed by a number of parties, is to incorporate Silicon into the graphite side of the Anode. Rather than a jump from carbon (graphite) based anodes to 100% Silicon only anode, what is being explored is adding around 20-30% Silicon with the balance remaining graphite.
Silicon particles have the ability to hold up to 10 times more Lithium ions than graphite alone but the relationship is not a linear one. As you can see from the bar chart below the addition of 10% (300-360 Wh/kg) then 20% (up to 420 Wh/kg) Silicon makes for the largest jump in capacity, with increases of additional 10% (30% only jumps to 440 Wh/kg) having a much lower impact in potential wh/kg.
Based on this 30% factor there are a number of different approaches as to how to integrate silicon into battery anodes. Silicon has a number of engineering challenges to meet in order to integrate into the anode of a Lithium battery.
Similar to a Graphite anode only, the first cycle capacity loss where lithium forms the SEI layer is proposed to be reduced with the addition of a HPA coating/shell. In the case of Graphite this first cycle capacity loss is around the 10% mark, however for Silicon anodes it is much higher around the 40-50% mark.
Silicon being able to hold up to 10 times more capacity, also increases in volume by up to 300% during the lithiation process. This can lead to the particle cracking & deteriorating decreasing the life of the battery.
“basically there are three problems the first problem is that silicon expands 300% in volume and it fractures. The second problem is that it has a very high first cycle loss so instead of 10% it’s more like 50% because there’s more sites that it can absorb lithium on. And thirdly it’s got a very high fade”
“volume expansion, so on lithiation the silicon particle expands 300% & it fractures. If you’re trying to put it into a battery and it starts to fracture you actually get delamination so you actually a lot of swell and it starts to lose contact with the copper plate that’s not what you want for a battery. So what the industry has been doing is they try it at larger particles one micron half a micron is still fractious and what they find is if you can get down to 150 nanometers.
A very small particle the volume expansion doesn’t create fractures …. but there are two problems the cost of getting to 150 nanometers – 1. very high costs in milling and also 2. The first cycle loss is even higher because of the surface ratio to volume ratio”
Iggy Tan New World Metals Conference – Session 2 Youtube presentation 54:50 mark.
In order to engineer around the limitations of Silicon as described above there are a number of different approaches, three of which are shown below – Vapour Method, Solids Method, Liquid Method.
- Vapour Method
Silicon Nanowires directly attaching to graphite particles is one solution that has been developed by a company called Sinanode.
This technology allows for faster charging & more power Wh/kg increasing range of battery.
Their technology solution minimizes equipment which can be ‘dropped’ in to existing anode production lines leveraging existing EV cell factories. In fact the scalability of the Sinanode approach, particularly for existing graphite anode manufacturers would be a big plus. Noting a single commercial CVD oven capable of treating 300MWh of anode active material up to 2GWh for larger size CVD ovens.
See also the Limiting Factor – Sinanode: Low Cost Silicon Nanowire Coated Graphite for OEMs
2. Solids Method (powder coated)
Novonix DMPG process would fall under this header – fusing nano-powders (solids) via mechanical means. This has been covered above for the cathode technology with in this case, coating both the graphite & Silicon particles with High Purity Alumina.
Talga Resources also coat their anode particles but with a graphene Silicon composite powder. Calling it a Chemo-mechanical process. I’m unable to find a resource that shows what is involved in this process.
Talga Resources // Natural Anode Dominance in Europe
3. Liquid Method
Tesla Polymer coated silicon material potentially solves the issue related pulverisation, delamination & the thick SEI layer. The limiting factor theorizes that this polymer/binder which Tesla uses could be Polyrotraxene which is a self healing elastic type binder.
#5 The Science Behind Tesla Silicon // Cracking the Silicon Code // Jordan Giesige
Altech Chemicals who have been developing a High Purity Alumina coating technology for Anode materials have identified what they believe to be the sweet spot in terms of processing cost & robustness for Silicon as an anode material at 500nm. Using a liquid Alumina precursor solution then calcinating to create in situ, a 2nm alumina coating.
Iggy Tan New World Metals Conference – Session 2 Youtube presentation 52:50
High Purity Alumina Coating also has been shown to improve the safety of Lithium batteries –
“use a nail and puncture a hole in the battery on the left-hand side it’s a non-coated graphite battery. Ttemperature rises and you get thermal runaway you can see the picture of the battery on the right hand side is a coated graphite gets to 90 degrees and virtually stops.”
Gen 2 – 100% Silicon
Sila Silicon have created a nano-structured Silicon particle which, as with the HPA coating process favoured by Novonix & Altech, creates an external shell around the Silicon which allows the transfer of electrons, but stops the swelling of the particle & associated fracturing, delamination issues that are associated with this.
“And the premise we kind of came to is we could build a structure, a composite super structure that allowed Silicon to expand and contract inside of a prescribed space reversibly while, while putting sort of an outer candy shell, if you will, on that prescribed space to make it look to the battery as if our, our composite particle is not swelling and contracting.”
Making the Forever Battery Steve Levine Interviews Gene Berdichevsky from Sila
Sila Nanotechnologies raises $590M to fund battery materials factory
Gen 3 – Ultra-Thin Li Metal
QuantumScape Lithium Metal solid state batteries – https://www.quantumscape.com/
Next, what’s anode-less mean? A conventional lithium ion battery uses copper coated with graphite for the anode. The graphite is a stable host structure that’s used to store lithium at 1 lithium atom for each 6 carbon atoms. With an anode-less battery cell, the anode is just copper with no coating. When the battery charges, lithium plates directly to the copper as lithium metal. This is the most energy dense way to store lithium metal at the anode because no bulky host structure is required. In other words, anode-less solid state batteries are actually one hell of an innovation because they replace two pieces of the core technology in a conventional lithium ion battery – the anode and the electrolyte.
The Promise of QuantumScape // First Principles Advantages
QuantumScape // Keep the Champagne on Ice
These writings about the technical aspects of batteries, components, supply chain and the like are intended to stimulate awareness and discussion of these issues. Investors should view my work in this light and seek other competent technical advice on the subject issues before making investment decisions.