New Battery Material Pegged As Breakthrough For Faster Charging

AUG 6 2018 BY MARK KANE 33

A new group of battery materials (niobium tungsten oxides) could lead to faster charging and high capacity lithium-ion cells for electric cars.

The team, consisting of researchers from the University of Cambridge, Argonne National Laboratory, Diamond Light Source, Harwell Science and Innovation Campus, have shown that micrometer-sized Nb16W5O55 and Nb18W16O93 provide higher capacity and energy density during fast charging (1C and 20 C) than nanoscale materials and formulations, which are complex and costly to make.

In other words, there is a chance that we will see batteries capable of ultra-fast charging, with decent energy density and at lower prices.

Niobium seems to be another go-to element as Toshiba is working on a new type of battery, which includes niobium, too.

Here is more about the research:

Niobium (Wiki)

“In their simplest form, batteries are made of three components: a positive electrode, a negative electrode and an electrolyte. When a battery is charging, lithium ions are extracted from the positive electrode and move through the crystal structure and electrolyte to the negative electrode, where they are stored. The faster this process occurs, the faster the battery can be charged.

In the search for new electrode materials, researchers normally try to make the particles smaller. “The idea is that if you make the distance the lithium ions have to travel shorter, it should give you higher rate performance,” said Griffith. “But it’s difficult to make a practical battery with nanoparticles: you get a lot more unwanted chemical reactions with the electrolyte, so the battery doesn’t last as long, plus it’s expensive to make.”

“Nanoparticles can be tricky to make, which is why we’re searching for materials that inherently have the properties we’re looking for even when they are used as comparatively large micron-sized particles. This means that you don’t have to go through a complicated process to make them, which keeps costs low,” said Professor Clare Grey, also from the Department of Chemistry and the paper’s senior author. “Nanoparticles are also challenging to work with on a practical level, as they tend to be quite ‘fluffy’, so it’s difficult to pack them tightly together, which is key for a battery’s volumetric energy density.”

The niobium tungsten oxides used in the current work have a rigid, open structure that does not trap the inserted lithium, and have larger particle sizes than many other electrode materials. Griffith speculates that the reason these materials have not received attention previously is related to their complex atomic arrangements. However, he suggests that the structural complexity and mixed-metal composition are the very reasons the materials exhibit unique transport properties.

“Many battery materials are based on the same two or three crystal structures, but these niobium tungsten oxides are fundamentally different,” said Griffith. The oxides are held open by ‘pillars’ of oxygen, which enables lithium ions to move through them in three dimensions. “The oxygen pillars, or shear planes, make these materials more rigid than other battery compounds, so that, plus their open structures means that more lithium ions can move through them, and far more quickly.”

Using a technique called pulsed field gradient (PFG) nuclear magnetic resonance (NMR) spectroscopy, which is not readily applied to battery electrode materials, the researchers measured the movement of lithium ions through the oxides, and found that they moved at rates several orders of magnitude higher than typical electrode materials.

Most negative electrodes in current lithium-ion batteries are made of graphite, which has a high energy density, but when charged at high rates, tends to form spindly lithium metal fibres known as dendrites, which can create a short-circuit and cause the batteries to catch fire and possibly explode.

“In high-rate applications, safety is a bigger concern than under any other operating circumstances,” said Grey. “These materials, and potentially others like them, would definitely be worth looking at for fast–charging applications where you need a safer alternative to graphite.”

In addition to their high lithium transport rates, the niobium tungsten oxides are also simple to make. “A lot of the nanoparticle structures take multiple steps to synthesise, and you only end up with a tiny amount of material, so scalability is a real issue,” said Griffith. “But these oxides are so easy to make, and don’t require additional chemicals or solvents.”

Although the oxides have excellent lithium transport rates, they do lead to a lower cell voltage than some electrode materials. However, the operating voltage is beneficial for safety and the high lithium transport rates mean that when cycling fast, the practical (usable) energy density of these materials remains high.

While the oxides may only be suited for certain applications, Grey says that the important thing is to keep looking for new chemistries and new materials. “Fields stagnate if you don’t keep looking for new compounds,” she says. “These interesting materials give us a good insight into how we might design higher rate electrode materials.””

Source: University of Cambridge via Green Car Congress

Categories: Battery Tech

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33 Comments on "New Battery Material Pegged As Breakthrough For Faster Charging"

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Too bad there aren’t any hard numbers in this report because right now Porsche is getting ready to offer 270wh/kg energy density that will charge to 80% in 15 minutes with no battery breakthrough needed, so I wonder how that compares to what Argonne labs is working on.

We have yet to see that in reality… 😉

True…When Porsche first announced this hypercharging I figured it was just some pie in sky numbers assigned to a prototype that would be dropped for the production car. However Porsche doubled down on this instead and has already started to roll out 350KW chargers on dealer lots so it’s pretty clear this is going to happen, even without some Argonne Lab breakthrough.

The 350 kW charging (or 80% in 15 minutes, i.e. 3.2 C average) isn’t actually outrageous in itself. Existing LFP can easily provide that, and existing LTO cells much more than that. Even power-oriented NMC cells (such as those used in PHEVs) can do such C rates today.

What makes me pause is the suggestion that they can achieve this power rating at 270 Wh/kg, which should still be near the top of the line for energy-oriented cells in 2019/2020…

Do we know if that energy density is specified at the pack level? Because there’s essentially three different ways to specify it: pack level, module level, and cell level. With the latter ones posting higher figures. If the Taycan battery does 270 Wh/kg at the pack level, that’s great; if it does the same at the module level, that’s already a substandard figure.

Cell level, obviously. Packs won’t come anywhere close to that for years.

And this is the same porsche that accused Telsa of lying about their semi truck numbers, and said that it required witchcraft to pull that off.
So, I agree with you. Something appears off on Porsche.

That was Daimler, not Porsche.

And what that does to the longevity of said battery. Even Tesla says you can charger faster, but faster isn’t always better and they chose to compromise speed with longevity. Perhaps Porsche consider it’s owners as less concerned with longevity as charging speed.

What I think Porsche is doing is using an oversized battery to make up for loss of lifespan. Looking at how tiny the car is + the size of the battery and range, it doesn’t make sense. So more than likely they threw lifespan into the wind and making it up with size.

But yes, studies have shown that even current batteries can be charged 10C (or about 6 minutes) without overheating if charged properly. But again, the lifespan is going to hurt.

In fact, Tesla tells car owners to NOT use the supercharger for daily charging due to lifespan.
The one single issue that they may have superHVAC on the batteries. If they have a good way of pulling off heat, then they can charge fast.
BUT, Porsche is using prismatics so, this does not make sense.,

It’s not all about cooling. If you try to force the ions into the anode faster than it can take them up, dendrites will form, regardless of temperature. Also, charging faster than a cell can easily accept requires higher voltage; and better cooling can only partially slow harmful parasitic reactions resulting from that. So charging speed is constrained by the cell design, not only cooling capacity.

There is plenty of hard numbers in this report — it’s just hard to estimate how this translates to actual battery cells based on these materials, which haven’t even started development yet…

Still, the graphs and text show that this is about power densities in the range of materials such as LTO or TNO, allowing charging literally in a couple of minutes — way faster than anything using carbon anodes.

BTW, I’m sceptical about the Taycan really having 270 Wh/kg. The press release brings up this number, but in rather circumspect wording… If it really does have 270 Wh/kg at 4C, that would be somewhat of a breakthrough in its own right as far as I’m aware.

“There is plenty of hard numbers in this report — it’s just hard to estimate how this translates to actual battery cells based on these materials, which haven’t even started development yet…”

That’s my assessment, too. This looks quite promising, but until they actually build some batteries with this material and test them to see how it works, it’s pretty much just one more thing that looks good on paper, and we see that kind of thing regarding new battery tech on a weekly basis these days.

I do find it encouraging to see that at least some research labs are trying to find truly new materials for batteries, and aren’t just fiddling around with tweaking cell chemistries that are already being used in production cells.

Actually, tweaking existing chemistries is mostly done by battery makers; while research institutions tend to focus on finding new materials, or analysing the nature and possible remedies to known issues.

If indeed Porsche has discovered some new secret sauce to higher density and faster charging speeds, will this result in cars that the masses can afford to buy?

Every new technology takes time to trickle down in able to truly be deemed “world changing”. Who cares that it can be done. Show me this capability in cars like a Model 3 or Y intended to be mass produced and I’ll tout Porsche as an innovator rather than a maker of boutique cars.

Gee, it can be done and sold to a few rich people and patented to prevent mass adoption. Should we hold Porsche in high esteem for such?

I very much doubt that Porsche has discovered some “secret sauce”. It’s pretty safe to assume that they are using more or less off-the-shelf cells; just choosing different trade-offs than other makers when selecting the cell type. (And selecting cells that will be mass-produced in late 2019, not today…) Other makers should be able to use the same kind of cell at that point, if they decide to accept the same trade-offs. (Whether higher price is one of those trade-offs, might become known in the future…)

That lithium polymer batteries used in the Hyundai Ioniq can easily charge at 2C, so it seems that now the main thing is to mass produce such batteries to get the cost down. Using such batteries in a 60 kWh EV would easily enable it to fast charge at 150 kW it would seem.

Everything else being equal, higher-power cells have lower energy density, and thus also somewhat higher costs per kWh…

Sounds more competitive with LTO than high demand NCA or NMC

It sounds like it should provide similar power densities as TNO or LTO, while also providing much better energy densities than either of these. This could actually make it competitive with current high energy capacity cells — though obviously not with the upcoming ones, using lithium metal anodes…

no need of faster charging batteries if you have cheap batteries . Cheap batteries allows big pack , so even at 1C you can get a very good charging power ( if you have a 200kwh pack charging at 1C is charging at 200kw )

The only problem with what you suggest is the energy density needs to greatly increase. By today’s standards, a 200kwh battery is a huge, heavy beast. Even if it is cheaper, it is physically too big to fit practically in most cars. In addition, it’s weight will significantly effect the handling dynamics of that car.

Regardless of charging speed, or energy density, cheaper batteries are significant though. If they could get the cost of a Chevy Bolt say that had the same 60kwh battery down to the cost of a Chevy ICE powered Cruze, that would be significant because then more people would see the value in TCO and also be more receptive to the idea of the BEV as a “second car”, or “commuter car”. As it is, once most people pay more than say $30,000 for a car, they have higher expectations for that car.

The true EV revolution won’t happen until nearly everyone sees the value in a BEV and can obtain one, not just the wealthy and trend followers.

If I want a BEV that will charge 300 miles of range in <10 minutes, that's gonna be a pretty durn big battery pack if it's not using significantly faster charging batteries!

The problem with just making the battery pack bigger for faster charging is that the car has to be bigger to hold it. Even if the batteries are cheap, they're not going to be low weight, and making the car bigger means the car is also more expensive, regardless of other considerations. A bigger, heavier car needs a bigger battery pack to power it… this is a vicious circle. At some point you hit the law of diminishing returns, no matter how cheap the batteries are.

Ultra-fast charging is going to demand batteries made to charge faster. Not just big-arse battery packs.

“niobium tungsten oxides”….sounds cheap.

Should currently be cheaper than Cobaltoxide per kg, but more expensive than other anode materials (the metals alone would cost about 3-6 times more than graphite currently does per kg, and the graphite is ready for deployment in the battery at that cost whereas the niobium-tungsten oxide has to be manufactured for additonal cost).
For some niche applications, the power density could be interesting, but it likely wil be heavy (whenever a graph says “volumentric energy density” or Wh per liter, or specific capacity per liter, one can trust that the gravimetric energy density is poor, and the cells will be heavy as hell. This will likely also not become widespread in cars, because of lack of niobium when compared to graphite, which can be made artificially, whereas niobium has to be mined.

Current cells use natural graphite instead of or in addition to synthetic, because it has a better structure.

Processing the graphite for the anode is actually quite expensive. Although the source material is comparatively cheap, cost estimates suggest that among the costs of a typical cell, the anode takes a similar order as the cathode…

While there is no doubt that tungsten is heavy, and niobium is not exactly lightweight either, with such an excellent volumetric density, the gravimetric density should still be decent… At least compared to current cells. By the time this research could make it into products, lithium metal anodes should be pretty standard, providing much higher energy density…

Indeed, processing the graphite is costly. Can even be the major share of the graphite cost when it goes into the cell. Those “cost estimates” suggesting that the anode is equal in cost as the cathode usually come from the same experts that believe that mass manufacturing of batteries is a few MWh per year with wholesale prices from back in 2010 (when that estimation was about right). For all mass market cells of today with graphite anodes that are produced in GWh scale, cost contribution is usually cathode > separator and then there is a gap before the rest (depreciation, the casing and passive components, labor, anode, electrolyte and the current collector foils).
Currently, graphite can be mined in China for 2500 $ per metric ton or less, and even the best Japanese stuff (highly processed) for EVs can be had below 10k$ per metric ton. Provided that one buys north of a few hundred metric tons per order. Indications that these prices are real can be found on Chinese alibaba, for example.

I wouldn’t trust any prices on Alibaba. Chinese manufacturers are notorious for screwing over the customer whenever they can get away with it. It’s the “wild west” over there, in the area of business; the concept of “business ethics” has yet to penetrate the culture. If you’re buying anything on Alibaba, then the principle of Caveat emptor (Buyer beware!) should be taken to the max.

Where did you get that information about cost contribution of the various parts of cell manufacturing? I’d be very interested in this kind of stuff…

(Also, why is the separator so expensive? That’s been puzzling me for a while…)

Niobium tungsten oxides seem superior in many ways, the best to me is simplicity and affordability in relation to capability.

Big questions are: The negatives of these oft-acclaimed stories speak brightly and positively of the upsides but sometimes glaze over the downsides.

The biggest downsides of THE latest new and improved material or technology are: Can it be patented, purchased and kept from those who would disrupt by actually using it? Is it easily adapted to current manufacturing and battery formats? In other words, could Panasonic, LG Chem, Samsung or Toshiba introduce these electrodes into thier current formats without building or rebuilding completely new new facilities and mechanisms to produce them?

In this article the downside is barely mentioned as operating at a lower voltage. How does that impact the efficacy of batteries containng these oxides and how does it negatively effect the prospect of using this in EVs and appliances anytime soon?

All good questions. Thank you!

Altho I’m not sure “not patentable” is really a barrier. Lots of products can’t be patented: common fasteners (nuts, bolts, screws, etc.); pencils; rubber bands. Looking at the objects littering my credenza, I see a pocket comb, an X-acto knife, nail clippers, and a metal ruler. I’ll bet none of those can be patented; the original patent would have run out long ago. That doesn’t stop companies from making and selling them at a profit!

I think he was suggesting that if something *is* patentable, some evil company could obtain a patent just to block it from coming to market at all… Allegedly that has been done with certain battery technologies in the past.