Featured CATL has new 500 Wh/kg battery

Again, for an EV battery to be practical, the pressure cannot be more than a few atmospheres. Ideally, you want a zero-atmosphere gauge pressure (ambient pressure), but you may be able to get away with a few atmospheres if the pouch energy density without the pressure fixtures is high enough. 130 atmospheres is way beyond that.

 

Maybe the key words are available and proven. Until them it resembles something Theranos might have said.

 

How is this news? QuantumScape's lithium-metal cell uses no lithium metal on the anode during manufacturing and does not require an expensive special coating as in this paper either. Moreover, it can work at ambient pressure.

"QuantumScape developed the industry’s first anodeless cell design, which delivers high energy density while lowering material costs and simplifying manufacturing."

Still, this does not make the cell economically viable. They have a lot way to go if they ever get there.

It is well known that you can make lithium-metal cells that perform well under extreme applied pressure.

So, nothing in this paper represents a major finding.

 

I have not read the paper, but I have stopped by the lab and talked to the research team (not involved but was interested, and on campus to talk to students) and seen the equipment. I have no idea what pressure will be needed in production but this is a lab experiment. This and others that has a great chance to help make lithium metal solid anode batteries more reliable and cheaper to manufacture. This link was about R&D and how to bring down manufacturing costs.

I am not sure who they are, or why they would think the sulfide electrolytes that toyota or solid power are using are not ceramics. You seem to have a problem with that technically correct word. I gave you the chemical formula of what they are using here, and it is a low priced sulfide. The only company showing data for their sulfide based solid state batteries is samsung and they require 20 atm of pressure. That really is not too hard to do in a battery pack. Toyota is using 700 atm in their hydrogen tanks. Toyota and solid power have not disclosed how much they need. Quantum scape says their non sulfide ceramic has an advantage of only needing 2 atmospheres. It makes no difference how chemicals are shipped, the toyota solid state will be solid not powder in the working battery. You say annealed that is a way of cooling, before that the solid is heated to a liquid.

Again solid power calls theirs a sulfide glass ceramic in techincal papers. Don't like the word don't use it, but don't be confused about what it technically is. I believe all these companies are working on multiple chemistries. Quantumscape had trouble with their sulfides and writes about technical problems to manufacture them, while others like the UT lab and corporations may be solving these.

 

What department are you in? It's good that you visited them.

As I explained, sulfide SSE users don't refer to it as ceramic. It could perhaps be described as a ceramic, glass, or ceramic/glass hybrid, but they just say sulfide. That's probably because the manufacturing process is similar to the cathode manufacturing process in conventional lithium-ion cells.

As I said, oxide ceramics like LLZO are harder to manufacture and they may require a separate process to generate the film before it's packed into the cell.

As for such research work, every bit could help. The pressure requirement is not encouraging. Could their coating help others? I don't know.

 

I think people are more worried about being attacked while they are charging their EVs than SSB development though.

 

I have no idea of what a good pressure for an EV battery would be.
But as a reference point, very common and cheap 1/2" schedule 40 used in homes and sprinklers has a max pressure of 500 psi and a burst pressure of over 2500 psi. That is 34 atm and 170 atm

PVC Pipes - Pressure Ratings vs. Size

Mike

 

I am not employed by the university, I received my graduate degree from there, I am a consultant now. I was on campus last winter to talk about supply chains, substitutions, and inflation. Sometimes I hire students and researchers to work on projects so that they can get some real world insight. One of my clients is a major auto company and I consult on some logistics software and changes to manufacturing. Its nice to see what is going on in current research.

I have no idea. Tell me the process and I may be able to tell you how to manufacture it cheaper. Right now they are still working on getting them reliable, small, and light. After that it is bringing down costs.

I am not even sure where you are getting the pressure requirement for this material. You are looking at a PEEK cell which researchers use to test battery chemistry. Here they specifically tested with and without the coating. The coating reduced dendrites compared to the same cell without the coating. The coating won't add much to manufacturing costs, and may even decrease them.

Any pressure required has to do with the electolyte anode and cathode selected and operating temperature. Quantumscape claims they need 2-3 atm with their non sulfide ceramic and lithium metal anode, they claim lower pressure requirements are one reason they chose their electrolyte. As mentioned early samsung requires 20 atm, toyota and solid power are stating but they must have a dendrite problem with lithium metal or else they would be using it instead of silicon or graphite.

 

I read the paper through my university library:

Stable anode-free lll-solid-state lithium battery through tuned metal wetting on the copper current collector (journal article) | DOE PAGES

The pressure they are using is 13 MPa (130 atm).

I do not consider "ceramics" as a material type but more of a fabrication technique. You can in principle have a so-called ceramic material prepared using crystal growth and have a crystalline material instead, without the usual grain boundaries of ceramics.

The SSE they are using is an argyrodite Li₆PS₅Cl. The manufacturing technique does not seem to be a ceramic technique. Here it is described:

Frontiers | Ionic and electronic conductivities of lithium argyrodite Li₆PS₅Cl electrolytes prepared via wet milling and post annealing

There are many types of sulfide SSEs, and a few are glass–ceramics and a few are ceramics:

Review of various sulfide electrolyte types for solid-state lithium-ion batteries

For an SSE, "oxide" or "sulfide" is a better descriptive term than "ceramic." That said, all oxide SSEs are probably ceramics, but only some sulfide SSEs are ceramics.

 

I think you are taking issue with something that has nothing to do with my point in posting the research.

Both Solid Power and Toyota want to use a sulfide with a solid lithium anode, but neither has been able to do it well for this first test, although toyota really hasn't disclosed what they are building. This research points to wetting a copper current collector then creating the lithium anode once the battery is built on the first charge. Using this method they decreased dendrite formation at the metal anode greatly. The wetting agent forms a thin layer (in this case 1 micron thick) between the solid electrolyte (a sulfide in this case) and an anode that can grow to 70 microns thick.

I was ignoring you pressure agument because it has nothing to do with this material science research that reduces manufacturing cost. The pressure needed has to do with the operating temperature and the materials. I assume that this would work fine but possibly with a different wetting agent with different lower pressure chemistries. Samsung says they have one that works at 20 atm. Solid power the last time they published was at 70 atm. I have no idea what the test cells from solid power or toyota need.

Further more it is not a crazy idea to have 130 atm of pressure in an automotive application, toyota does this at 700 atm with their fuel cell vehicles and must deal with the pressure. It is too high to expect a mechanical metal only device to maintain but hydraulic tools often work at 700 bar (690 atm), and its fairly straightforward to build a casing pressurized with a non flammable hydraulic fluid to work happily at 150 bar. Certainly it would be cheaper and easier to work with a battery that was good between -40 and boiling, and at 1/2-1 atm of pressure, but no battery works at all of these things. The question is the size, cost, weight, and performance of the system. I really don't expect the winning candidate to need pressure anywhere near this, but it does not stop something from being tried.

I use the word as a type of material, not a manufacturing method. Use it any way you please but don't correct others if they are using it correctly. I fully expect that if the winning candidate ceramic non sulfide or sulfide glass ceramic will be cold sintered then heat treated.

 

No, Solid Power is not working on a lithium-metal-anode battery. They are working on a 50%-silicon/50%-carbon-anode battery. They originally started with a lithium-metal battery, but it did not quite work. They might go back to working on it in the future. They recently received a grant from DOE on a small lithium-metal side project, but that is different.

No, you do not understand the difference between hydrostatic pressure and mechanical pressure. It is easy to maintain pressure in a tank containing a gas. In a battery, it is mechanical pressure, which is applied using pressure fixtures that are simply two parallel metal plates fastened together with torqued nuts and bolts. There are two problems with this. First, they greatly decrease the energy density, especially if the pressure is large and the fixtures are heavy/extra duty. Second, unlike in a hydrostatic-pressure vessel where the pressure is uniform, it is extremely difficult to apply a uniform pressure. It becomes harder and harder to apply a uniform pressure when the pressure gets higher and higher. Any nonuniformity in the pressure results in quick cell failure.

The third point that you do not get is that you can make any solid-state cell work by applying a high-enough pressure or a high-enough temperature. Therefore, when someone comes saying that they might have built a cell that works at 130 atm or 1,300 atm, I simply ignore it.

Any material and technique used—oxide, sulfide, ceramic, plastic, etc.—needs to be scalable. Building a 100-GWh/yr factory requires an incredible manufacturing capacity.

 

Yes exactly, and this coating shows lots of promise. Other research institutions also are working on different materials, as well as multiple solid electrolytes used in combination.

I think the commercialization of the lithium battery are instructive to this discussion of solid and semi solid state batteries. British American Whittingham invented the lithium battery while at exxon during the 1970s energy crisis, which was funding pure research. Exxon did sell some that got used in a solar watch. Goodenough found a better cathode material making the battery less prone to dendrites. Still the batteries were not good enough for plug in cars. Akira Yoshino in Japan used a carbon (Coke) anode and Goodenough's cathode, to create a commercial lithium battery. The 3 men shared the nobel prize in 2019.

https://news.uchicago.edu/story/how-john-goodenough-sparked-wireless-revolution

At 100 years old Goodenough is still working on solid state batteries. Professor Barga created a new solid state electrolyte and started working with him in 2015.

 

Perhaps we need another thread that outlines the different battery architectures:

• Carbon-zink - primary cells
• Lead acid - sulfuric acid base
• Nickel iron - 1900s EV batteries
• Liquid cathode and anode cells - energy storage
• NiMH - our favorite Prius cells
• NMC - early LiON cells
• LiFePO - newer cells
• Aluminum Air - primary cells
• ...

This is not a trivial task and someone (Wiki?) may have already done this. Rather, it would remind us of the options.

Bob Wilson