Batteries new life for energy storage

Published on December 19th, 2014 | by Tina Casey

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Two Nifty Little Nanoscale Lifts For Energy Storage

December 19th, 2014 by  

Just when you thought the world was ready to move beyond lithium batteries, along comes a new discovery that shows how much more juice we can squeeze out of the technology. On the other hand, lithium has been the gold standard for energy storage in a slew of clean tech fields including electric vehicles and large-scale stationary batteries, but it’s beginning to bump up against some competition from other areas.

By other areas we mean sodium batteries. You thought I was going to say fuel cells, right?.

new life for energy storage

Nanoscale pattern drawn by atomic force microscopy (courtesy of ornl).

Advanced Energy Storage: Use The Force!

First, let’s take a look at some nano-news in the lithium-ion energy storage field. The item that caught our eye deserves a group hug from all you taxpayers out there, because it comes out of our Oak Ridge National Laboratory.

This is one of those surprise discoveries where you set out to do one thing, and you accidentally discover something else that’s much more exciting.

The research team was trying to measure the properties of polymerized ionic liquid thin films, a highly conductive material with a “unique” structure that has promising applications for lithium batteries and solar cells.

 

An ionic liquid refers to a salt in liquid state. Through polymerization into the mix (polymers refer to materials composed of similar molecules, typically in a long chain), and now you’re cooking with gas.

To measure the conductivity of polymerized ionic liquid, the team dusted off their trusty atomic force microscope. That’s not entirely a new thing, since the gizmo is commonly used to study non-conductive polymers, and to produce patterns in them.

The team didn’t expect the pattern thing to happen, but it did. The microscope bored nanoscale holes in the material.

That’s exciting because this kind of nanoscale lithography is becoming common in clean tech manufacturing and other nanoscale fields, but not at quite such a tiny scale. What you’re looking at is the potential for fabricating smaller, more powerful batteries while putting less energy into the manufacturing process.

The team also found that the process used far less energy to make patterns on their conductive material, compared to the same process used on non-conductive polymers.

The difference is that when applied to a non-conductive material, the holes are formed by highly localized heating. The team’s material, in contrast, kind of self-assembled its own holes when negative ions migrated to the positively charged tip of the microscope.

Here’s the next step according to study co-author Vera Bocharova:

Right now the size of the formed features is in the range of 100 nanometers, but it’s not the limit.  We believe it’s possible to change the experimental setup to advance to lower scales.

If you want to see the details, look for “Controlled Nanopatterning of a Polymerized Ionic Liquid in a Strong Electric Field.”

Don’t Look Back…

As Satchel Paige famously said, “Don’t look back. Something might be gaining on you.” Obviously he was telling lithium batteries to watch out for sodium batteries, in this case enhanced by a form of graphene.

For those of you new to the topic, we have tirelessly described graphene as the nanomaterial of the new millennium for its practically limitless clean tech applications, including next generation solar cells as well as lithium electric vehicle batteries and other forms of advanced energy storage.

Graphene refers to a sheet of carbon just one atom thick. It possess Superman-style strength and unique — and powerful — conductive properties, but it is difficult to fabricate and work with.

That’s where graphene oxide comes in. It’s a “defective” form of graphene that functions as an insulator. However, when it is heated it can become a conductor or semiconductor.

An engineering team at Kansas State University took a look at the behavior of sheets of graphene oxide “paper” when used as electrodes in sodium-ion and lithium-ion batteries. Here’s the money quote from c-author Gurpreet Singh:

Most lithium electrode materials for sodium batteries cannot even last for more than a few tens of charge and discharge cycles because sodium is much larger than lithium and causes enormous volume changes and damage to the host material. This design is unique because the distance between individual graphene layers is large enough to allow fast insertion and extraction of the sodium ions, thanks to the oxygen and hydrogen atoms that prevent sheets from restacking.

Specifically, the study showed that the graphene oxide paper sheets withstood more than 1,000 charge/discharge cycles. That’s a big improvement over past experience with lithium electrode materials for sodium batteries, where the cycling can be counted in tens.

Not to worry, lithium-ion. Singh foresees that sodium batteries will find a place in large scale stationary energy storage, not so much in mobile energy storage for electric vehicles.

But, you never know…

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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.



  • Vensonata

    Somebody needs to do a new article on Aquion sodium batteries, which are for sale to the public both for residential and commercial scale. They match lifepo4 (lithium batteries) in all parameters except weight. They weigh about the same as lead acid. But they surpass both lithium and lead acid for safety. They are non explosive, do not off gas, and if you are really hungry you could theoretically eat one without injury. Lifecycle cost at residential price is about 10 cents kwh (5000 cycles for$500 kw) at commercial scale they are talking $250 kw…so 5 cents kWh. By the way they match quality lithium batteries in that they get 3000 cycles to 100% depth of discharge. Not even the best industrial lead acid can do 50% of that.

    • Vensonata

      Update. Check out Real Goods Solar store, they sell them and have a pdf about a real customer on a ranch in California that is using a 60 kwh Aquion battery bank with a 14 kwh PV array off grid. Good info pricing etc. Real Goods have been around forever so quite reliable

      • Offgridman

        Thank you for keeping track of this tech and the update on availability for residential customers.
        Storage replacement is hopefully still quite a few years off in the future for myself, but it is good to know that more options are becoming available. Especially ones that safer to handle and will need less maintenance and/or monitoring.
        This has also been a timely reminder to get myself signed back up to get the sales catalog/magazines from Real Goods that stopped coming a year or two ago. Not only do they have interesting stories on people that are using renewable energy, but make a convenient educational handout to others that are curious about doing so.
        Hope that you and your household have a blessed and enjoyable solstice/midwinter holiday and New Year.

        • Vensonata

          OffGridMan Yes, these batteries are financed by none other than Bill Gates and have been a few years in the making. The Engineering prof. who pulled it off is from Carnegie Mellon and also did reputable research on lithium batteries before. His idea was to use cheap plentiful substances that were utterly benign. Brilliant. And here 5 years later it has arrived. Because of the materials involved it could truly become the cheapest best option. I think they set the price simply as competitive to lead acid and lithium not much to do with actual production cost, which I suspect is far less than the competition.

          As all off grid people know Off Grid Man the shortest day approaches, but the sun king returns soon!

          • Offgridman

            “Sun King returns soon!”
            As he always has and always will, so far as our limited frame of reference anyways. 🙂
            After some checking around on AltE it seems that the Aquion compare quite favorably for size with lead acid. Their pallet sized industrial pack has almost three times the usable energy of my sealed lead pack that measures four feet wide by five high and 32 inches deep. Didn’t see a weight but doubt it can be any worse than the 3450 lbs of mine.
            As they state too, no maintenance or management needs for the life of the pack either. I am now down to just a monthly equalization, but being able to leave a system for my sons that they can go off for months or years to enjoy their lives and come back to still find working is important to me.

      • ADW

        Didn’t see them on Real Goods. but did find it at altestore.cpm
        $1,155.00 51Ah 48V.

        • Vensonata

          Yeah, mysterious isn’t it! Real Goods don’t have them listed but they have a model installation at that California ranch with complete science data. I expect that they are being cautious and protecting their reputation. Or we here on Clean Technica are just a little ahead of the curve and Aquion batteries will be listed in a few months. They are definitely ready for prime time.

  • Matt

    Dirt cheap but heavy batteries are a fine solution for stationary applications. Don’t have to have the same single solution to all. Of course this one is not even a gleam in a manufactures eye.

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