MIT "Yolk and Shell" Nanoparticle Promises Longer-Lived Rechargeable Batteries

jan_jes writes: A new "yolk-and-shell" nanoparticle created by researchers at MIT and Tsinghua University in China could boost the capacity and power of lithium-ion batteries. The researchers have created an electrode made of nanoparticles with a solid shell, and a "yolk" inside that can change size again and again without affecting the shell. The new findings, which use aluminum as the key material for the lithium-ion battery's negative electrode, or anode, are reported in the journal Nature Communications. The use of nanoparticles with an aluminum yolk and a titanium dioxide shell has proven to be "the high-rate champion among high-capacity anodes." The linked article goes into much more detail about the (serendipitous) discovery.

Comments

Wow...

[Dr_Barnowl]

TLDR?

• * > 3 x the charge density of carbon cathodes
• * Still has nearly double the charge density of carbon after 500 balls-to-the-wall rapid charge cycles (6 minutes)
• * Made of very cheap stuff - we package soda in aluminium and slather titanium dioxide on our bodies and then wash it away, ferchissakes

Very, very exiting. I imagine they'll be getting a call from Elon Musk in their near future.

Re:Wow...

[Rei]

Indeed, aluminum is the 3rd most common element in Earth's crust (more common than iron), oxygen is the most common, and titanium the 9th most common (more common than hydrogen). Now, of course, it's not elemental abundances that matter but raw feedstock prices. Their feedstocks are 50nm aluminum powder, sulfuric acid, and titanium oxysulfate. Concentrated sulfuric acid is one of the most widely used industrial chemicals on the market, cheap at about $700 a tonne. Even high purity sulfuric acid isn't particularly expensive. Titanium oxysulfate is about $5000 a tonne - still really trivial compared to the value of the anode material you're getting. However: 80nm aluminum nanopowder (in the same size ballpark) costs $1109 per kilogram, and that's the cheapest I've found online that has a price quote. And this here is a big problem, that's just way too expensive, your finished batteries will be selling for something in the ballpark of $100/kg. But, this is small scale. If anyone here has any idea how cheaply 50nm aluminum powder could be made if desired in quantities of hundreds of tonnes a year, I'd be quite curious.

Of course, as pointed out below, the sort of news we really want to see is about significant cathode improvements...

Re:Wow...

[Anonymous Coward]

I don't know anything about the specifications or manufacture of such things, but nano-tek.co.uk appears to have 30nm powder, possibly in a lower quality, for £2000/metric ton (£2/kg). There's quite a variation there, perhaps due to quality control rather than manufacture per se. I guess a lot depends on if the process needs 100% pure spheres or if the process can cope with 90% spheres and filter out the bad anodes later.

Re:Wow...

[Rei]

Wait a minute.... it says mean size 30 *micron*, not 30 *nanometers*. Sorry - the particles are 600 times too large :(

Re:Great, but...

[Rei]

For those interested in the current state of cathodes in li-ion batteries and the research underway to improve them, there's a good paper here. The short of it is that they do keep making incremental improvements, and might continue that way for a long time, but they don't seem to be as subject to the "big leaps" that people are working towards on the anode side. There's been some interesting work since then, though - for example they don't mention anything about the recent work on vanadium/boron glasses (~300Mah/g initial capacity (twice that of LFP), without as much degradation as with forms of crystalline vanadium oxide)

Honestly, I don't expect any "big leaps" overall in battery tech. But based on everything I've seen that's already "in the pipeline", incremental improvements in li-ion battery capacity should be expected to continue to improve for at least 5 years, and probably much longer. There are a number of proposed techs for what will come after li-ion. I personally wouldn't be surprised if lithium-sulfur becomes the next usurper - it has huge capacity, generally common materials, there's been a lot of work towards overcoming its main downside (short lifespan), and there's already a low-volume manufacturer out there PolyPlus with limited use in special applications.