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Soon your floor could charge your electric razor, toothbrush, radio, or even double for solar storage

Researchers at Rice University have developed highly unorthodox batteries that can literally be painted onto a variety of surfaces, including "ceramic bathroom tiles, flexible polymers, glass, stainless steel, and even a beer stein."

I. Designing Paintable Lithium Ion Batteries

The research team, funded by grants from the Advanced Energy Consortium, the National Science Foundation, the U.S. Army Research Laboratories, and Nanoholdings Inc. succeeded in their goal of creating stable batteries, overcoming early issues of the separation layer peeling away from the tile which ruined the battery.

The finished design is capable of putting off 2.4V of power.  Total capacity and current output vary, but the design is lithium based, so it should be in line with the batteries found in today's personal electronics devices.

The design is composed of four layers, much like traditional cells.  

The first step of the process was to paint a cathode current collector material.  Aluminum paints were considered too toxic and reactive, so they were ruled out.  Instead, the researchers use purified single-wall carbon nanotubes with carbon black particles dispersed in N-methylpyrrolidone for this step.   

The next layer in the painting process is the cathode.  The cathode contains lithium cobalt oxide, carbon, and ultrafine graphite (UFG) powder in a polyvinylidine fluoride (PVDF) "binder" solution in NMP.  PVDF is a low-cost binder that is used in many premium color paints, such as the metal paints used on the Petronas Towers in Malaysia.

II. Separator Posed the Biggest Hurdle

The third layer, which is eventually hydrated with electrolyte and separates the cathode and anode is perhaps the most critical.  Early designs had stable cathodes and anodes, but had the separator layer peel away, ruining the battery.  The issue was that at certain voltages, the separator had a tendency to lose its integrity, hence peeling off.

Researchers eventually found that using Kynar Flex resin, they could accommodate a wider voltage range.  They mixed the KynarFlex with PMMA and silicon dioxide dispersed in an acetone and N,N-Dimethylformamide (DMF) solvent mixture.  That formulation did the trick and kept the layers stably attached.

The fourth layer forms the anode.  It is composed of lithium titanium oxide carbon black, and UFG.  It was turned into a paint using the same PVDF (binder) and NMP (solvent) mixture used in the cathode. Lastly, a copper paint is applied to the anode.

Rice battery airbrushing
The battery is sprayed on in four layers. [Image Source: Jeff Fitlow]

The battery's separator layer is then soaked in electrolyte, allowing the separator to take up the necessary electrolyte.  The finished cell is then sealed using laminated poly(ethylene)-aluminum-poly(ethylene terephthalate) (PE-Al-PET). 

In tests the Rice researchers used a series of nine tiles, powered by a solar panel, to illuminate a series of light-emitting diodes that spelled out "RICE".  

The testing results and a description of the materials/process is published [full-text] in the peer-reviewed open Nature journal Scientific Reports.  

The first author was Neelam Singh, a grad student and the senior author was materials engineering professor Pulickel Ajayan.  

Rice University team
Right to left: Charudatta Galande, Professor Pulickel Ajayan, and lead author Neelam Singh
[Image Source: Jeff Fitlow]

Other co-authors include Charudatta Galande and Akshay Mathkar, alumna Wei Gao, and research scientist Arava Leela Mohana Reddy, all of Rice; Rice Quantum Institute intern Andrea Miranda; and Alexandru Vlad, a former research associate at Rice, now a postdoctoral researcher at the Université Catholique de Louvain, Belgium.

III. Outlook

The chemicals used are not without its downsides -- namely some of the compounds are somewhat toxic and would thus require careful disposal.  In addition to the dangers of lithium, studies have shown that both NMP and DMF can lead to birth defects or reproductive issues.  Additionally, the DMF solvent has been linked to cancer in humans.

Rice battery stein
You might want to be careful drinking from that Stein. [Image Source: Jeff Fitlow]

Likewise, lithium is a scarce resource, primarily controlled by China.  With electric vehicle makers already vying for production, costs for the novel batteries could become increasingly high.

Still the idea of being able to quite literally paint a lithium ion battery onto a wealth of form factors, including ceramic floor tiles could offer a big step forward towards both "smart" houses, and to storage of home-generated solar power.

Rice battery + LEDs
The new battery could help homeowners get "off the grid". [Image Source: Jeff Fitlow]

Rice University and Nanoholdings Inc. are looking to commercialize the process and have filed a patent on it.  Soon people looking to live "off the grid" with solar panel installations may be able to quite literally store their excess daytime solar energy in their floor.

Sources: Scientific Reports, an open Nature journal, Rice [Press Release]

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By Florinator on 6/29/2012 4:50:34 PM , Rating: 5
For all Jason Mick haters out there: how was this for a "well-written, balanced, and informative entry"? You asked, he delivered! :-)

RE: Question
By bah12 on 6/29/2012 5:49:54 PM , Rating: 3
I'll admit I jump on that dog pile from time to time.

Very well done Jason. However, this just illustrates why he drums up drama whenever possible as this article is at a lowly 5 posts :)

Lets face it drama sells.

RE: Question
By futrtrubl on 6/30/2012 1:49:04 AM , Rating: 2
Well except that 2.4V is not power and this 4 layer cell is made of 5 layers.....

Where will this be used?
By topkill on 6/30/2012 1:12:22 PM , Rating: 2
Interesting research, and I hope something good will come out of it. I'm just having trouble trying to decide what problem this is solving?

We need lower cost Li batteries, does this pass that test? I doubt it? Higher energy or power density? Doubt it.

I've seen Lithium batteries built as part of the support structure for a vehicle so it saves overall weight in the car because without it they would have had to put in steel, aluminum or carbon fiber in those same structures so I get that one.
If you're storing energy for a home or solar want the cheapest, and most long lasting battery, not something that can be sprayed on a surface. There is no advantage to that.

What advantage could this have? I'm not trying to be a dick, I'm asking a serious question and hope someone has ideas???

RE: Where will this be used?
By Manch on 7/2/2012 5:54:18 AM , Rating: 2
It can solve several problems. Your example of the the Li battery as part of the support structure. In order to make that happen, that takes a lot of reinforcement to the casing and that adds weight. Weight distribution is critical in a car, especially a sports car. With this "paintable" battery, the entire support structure could be the battery. Imagine a car whose frame is the battery, to include the body panels. The ability to distribute the weight evenly has the benefits of making the car lighter becuase you have no need to for a this heavy casing. Eliminating that box opens up the design of the vehicle. It will also reduce your cooling requirements, which is a big issue for electric vehicles.

Have you seen the infamous top gear episode about the tesla roadster. The weight of the batteries compromise its handling. A redesign of that car using this technology could make for a far more capable car, and maybe one that can last longer.

This may not be a more efficient battery than a regualr Li, but the ability to customize the battery into infinite shapes can do wonders for critical applications where weight distribution is a huge factor.

Other things off the top of my head:

Backpack frame turned into a battery, combine these with shock system to generate and store electricity.

Guard rails ont he highway turned into batteries to collect electricity from solar panels for street lights.

Roofs as batteries(combine these wioth solar shingles)

prostetic limbs that are also the battery used to run them. That would be better than a battery pack on your waist.

RE: Where will this be used?
By topkill on 7/6/2012 12:45:00 PM , Rating: 2
No, your missing the point. The "structural batteries" I was talking about were examples of where the battery material itself WAS the support. It didn't require something around it and so therefore it saved weight.

This just spreads the weight out like an extra layer of paint. If you're looking to locate the weight better, it's easier to have it in small, flexible shapes that can be put anywhere in the vehicle. Red Bull does this in Formula 1 and actually molds their storage system in as part of the floor structure.

If you have to spray it on, then it either has to be able to COMPLETELY take the place of the existing paint layer or else it's just adding more weight again.

RE: Where will this be used?
By Manch on 7/7/2012 8:01:57 AM , Rating: 2
The battery itself is not load bearing tho. Its casing is. They may put the battery inside a support structure, but its not the battery itself. Whats more mold-able than paint?

RE: Where will this be used?
By sunjava04 on 7/2/2012 6:50:29 PM , Rating: 2
dude, just appreciate what they did. u cant predict where its gonna be helpful.

Corning gorila glass was invented way earlier approx: 1960's but it was kind of useless until iphone arrived, now look at everything uses it from pad to smartphone.

variety of uses
By magreen on 6/29/2012 3:16:24 PM , Rating: 5
In tests the Rice researchers used a series of nine tiles, powered by a solar panel, to illuminate a series of light-emitting diodes that spelled out "RICE".

Researchers believe the tiles can also be used to illuminate any letters other than "U" and "T".

Now that is some...
By msheredy on 6/29/2012 2:44:21 PM , Rating: 2
...trick chit right there!

So thats what it is...
By dj LiTh on 6/29/2012 4:52:01 PM , Rating: 2
I was wondering what that tingling in my balls was.

By bobsmith1492 on 6/29/2012 5:54:08 PM , Rating: 2
"2.4V of power"

Volts are not a unit of power. Electric power = Volts x Amps in units of Watts.

"A lot of people pay zero for the cellphone ... That's what it's worth." -- Apple Chief Operating Officer Timothy Cook

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