University of Waterloo Develops Flash Heat Treatment Process For Si-Based Anodes For Li-ion Batteries

DEC 23 2013 BY MARK KANE 14

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New battery technology breakthroughs appear almost daily it seems, but this latest development done by the University of Waterloo and General Motors seems promising.

The research focused on Si-based anodes for li-ion batteries, which as we know have high capacity, but are not too durable.

The team from the University of Waterloo boosted performance by adding a new process called Flash Heat Treatment.

According to the study, treatment at 900°C for 20 minutes makes the anode material more durable and able to last 500 cycles (or perhaps more, as the graph does not show a high rate of fall off) without too much capacity fade at 1C currents (1-hour currents).

1C isn’t a big deal for EVs, but with at least 2 times more energy in the same mass, they are still an attractive option for some automotive applications.

Engineered Si Electrode Nanoarchitecture: A Scalable Postfabrication Treatment for the Production of Next-Generation Li-Ion Batteries

“A novel, economical flash heat treatment of the fabricated silicon based electrodes is introduced to boost the performance and cycle capability of Li-ion batteries. The treatment reveals a high mass fraction of Si, improved interfacial contact, synergistic SiO2/C coating, and a conductive cellular network for improved conductivity, as well as flexibility for stress compensation. The enhanced electrodes achieve a first cycle efficiency of 84% and a maximum charge capacity of 3525 mA h g–1, almost 84% of silicon’s theoretical maximum. Further, a stable reversible charge capacity of 1150 mA h g–1 at 1.2 A g–1 can be achieved over 500 cycles. Thus, the flash heat treatment method introduces a promising avenue for the production of industrially viable, next-generation Li-ion batteries.”

We don’t know if this really works in the real world or if this is a viable method, but Flash Heat Treatment is an interestingly simple development.

Hopefully, longer range, cheaper EVs are just around the corner, but way back in 1908 Poynter W. Adams hoped for that too.

Source: American Chemical Society via Green Car Congress

Categories: Battery Tech


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14 Comments on "University of Waterloo Develops Flash Heat Treatment Process For Si-Based Anodes For Li-ion Batteries"

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This was a good article. Doesn’t the Sulfer battery GM was supposed to be working on have this kind of Anode?

I don’t know about GM, but the current Panasonic batteries that Tesla uses are Si.

There probably isn’t going to be a heck of a lot of comments on this one. So I’m just going to wade in here and say that I enjoy these type of updates/stories from time to time – a nice change of pace…although I do realize it does still seem to be a little self-serving saying that, all things considered.

Anywhoo, props to Mark, (=

It’s the views not the comments that count 😉

I like to see these kinds of articles spread within the bread-n-butter EV stuff. It shows the real complexity of the tech.

It does sound promising, because it seems like a relatively simple process, and not as far fetched as some of the other ideas that have been floated out there. It would be nice to see some breakthroughs that are still promising once they get to real world testing.

500 cycles still isn’t very good. The only way around that issue is to do like Tesla and use a huge battery pack so that daily driving will only cycle the battery a very small amount.

So I don’t guess this type of battery will be much good for plug-in hybrids or low-range EVs like the Leaf.

If this development, perhaps combined with others, can bring the capacity to double the current cells, then a $29K Leaf would be a 150 mile car charging half as often.

That’s many years down the road. Developments like this will first find their way into premium batteries for cellphones. Double density and you can get $2/Wh easily. When competitors start figuring this tech out and produce enough to cover the rest of the market, then we’ll start seeing prices drop, and finally enter the auto market.

So you’re looking at a decade at least. The real way that the Leaf will get more range is by packing in more of today’s batteries.

Of course it is years down the road. Don’t you think Nissan thought of “packing in more of today’s batteries?” You get diminishing efficiency, and/or higher price. People will have to change their expectations very soon. Manufacturing isn’t going to get cheaper in coming years.

or one normal capacity battery pack (that can handle the re-gen braking and frequent charging) for daily work and then a bigger battery (that is still re-chargeable but might not handle the high number of cycles) for the longer distance travel to Grandma’s at the weekend. Tesla have put in a patent on this concept although, IMO, I don’t know how valid it is as there must have been plenty of cars that have had 2 types of battery in them over the years but what do I know I’ll leave that one to the lawyers.

500 cycles is good enough for long range EVs – a battery with 300 miles real-world range would get 150,000 miles out of a pack before it hit 80%. Not bad if you’re driving 15K/yr.

I wouldn’t want this backing up grid power though.

Yeah, but if, after 500 cycles, the anode is still 3x as good as the graphite anodes most commonly used today even when new, then it’s still a huge improvement.

Cost is what really matters here. Hard to say if it has a lower cost floor than graphite.

You can afford to go to a more expensive cathode or anode if it increases range energy density enough. This is shown in the Argonne paper. NMC is an example.

First use of these higher capacity batts will be military where high density, high capacity but mid-level charge count is ok. Such as for battery standyby systems in the field or low use-count vehicles or drones.