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Making high-performance batteries from junkyard scraps

by | Nov. 2, 2016, 9:00 AM | Want more research news? Subscribe to our weekly newsletter »


Share this on Facebook "MacGyver-ing" high-performance batteries out of scrap metal, laundry soap and a glass jar
Each year the U.S. produces hundreds of millions of tons of metal scrap like this, which was photographed at the PSC Metals scrapyard in Nashville.(Vanderbilt University)

Each year the U.S. produces hundreds of millions of tons of metal scrap like this, which was photographed at the PSC Metals scrapyard in Nashville.(Daniel Dubois / Vanderbilt University)

Take some metal scraps from the junkyard; put them in a glass jar with a common household chemical; and, voilà, you have a high-performance battery.

“Imagine that the tons of metal waste discarded every year could be used to provide energy storage for the renewable energy grid of the future, instead of becoming a burden for waste processing plants and the environment,” said Cary Pint, assistant professor of mechanical engineering at Vanderbilt University.

research team at junkyard

Cary Pint, right, Andrew Westover and Nitin Muralidharan, who is holding the prototype junkyard battery they created in his left hand. He and Westover are holding bottles of the common household chemicals used in the process. (Daniel Dubois / Vanderbilt University)

To make such a future possible, Pint headed a research team that used scraps of steel and brass – two of the most commonly discarded materials – to create the world’s first steel-brass battery that can store energy at levels comparable to lead-acid batteries while charging and discharging at rates comparable to ultra-fast charging supercapacitors.

The research team, which consists of graduates and undergraduates in Vanderbilt’s interdisciplinary materials science program and department of mechanical engineering, describe this achievement in a paper titled “From the Junkyard to the Power Grid: Ambient Processing of Scrap Metals into Nanostructured Electrodes for Ultrafast Rechargeable Batteries” published online this week in the journal ACS Energy Letters.

The secret to unlocking this performance is anodization, a common chemical treatment used to give aluminum a durable and decorative finish. When scraps of steel and brass are anodized using a common household chemical and residential electrical current, the researchers found that the metal surfaces are restructured into nanometer-sized networks of metal oxide that can store and release energy when reacting with a water-based liquid electrolyte.

The team determined that these nanometer domains explain the fast charging behavior that they observed, as well as the battery’s exceptional stability. They tested it for 5,000 consecutive charging cycles – the equivalent of over 13 years of daily charging and discharging – and found that it retained more than 90 percent of its capacity.

Unlike the recent bout of exploding lithium-ion cell phone batteries, the steel-brass batteries use non-flammable water electrolytes that contain potassium hydroxide, an inexpensive salt used in laundry detergent.

“When our aim was to produce the materials used in batteries from household supplies in a manner so cheaply that large-scale manufacturing facilities don’t make any sense, we had to approach this differently than we normally would in the research lab,” Pint said.

The research team is particularly excited about what this breakthrough could mean for how batteries are made in the future.

“We’re seeing the start of a movement in contemporary society leading to a ‘maker culture’ where large-scale product development and manufacturing is being decentralized and scaled down to individuals or communities. So far, batteries have remained outside of this culture, but I believe we will see the day when residents will disconnect from the grid and produce their own batteries. That’s the scale where battery technology began, and I think we will return there,” Pint said.

The Vanderbilt team drew inspiration from the “Baghdad Battery,” a simple device dating back to the first century BC, which some believe is the world’s oldest battery. It consisted of a ceramic terracotta pot, a copper sheet and an iron rod, which were found along with traces of electrolyte. Although this interpretation of the artifacts is controversial, the simple way they were constructed influenced the research team’s design.

The team’s next step is to build a full-scale prototype battery suitable for use in energy-efficient smart homes.

tiny string light illuminated with battery

Prototype of high-performance junkyard battery powering a small light. The researchers next step will be to produce a full-scale version suitable for use in energy-efficient smart homes. (Pint Lab / Vanderbilt University)

“We’re forging new ground with this project, where a positive outcome is not commercialization, but instead a clear set of instructions that can be addressed to the general public. It’s a completely new way of thinking about battery research, and it could bypass the barriers holding back innovation in grid scale energy storage,” Pint said.

Co-authors on this project include Nitin Muralidharan and Andrew Westover who co-led the project and are graduate students in the interdisciplinary materials science program, Nicholas Galioto and Haotian Sun, who are both Vanderbilt mechanical engineering undergraduate students; Rachel Carter and Adam Cohn, who are graduate students in mechanical engineering; and Landon Oakes, who is a graduate student in the interdisciplinary materials science program.

The work was supported by the National Aeronautics and Space Administration EPSCoR grant NNX13AB26A, the National Science Foundation graduate fellowship program under grant 1445197 and a Vanderbilt Discovery Grant. The team worked with Matt McCarthy at PSC Metals, who provided access to its scrap metal facility in support of this project.

Media Inquiries:
David Salisbury, (615) 322-NEWS

  • Aaron Blake

    I would like to know when there are plans and/or instructions on how to do this myself at home with my own off-grid PV system. Better yet, I’d like to buy a kit that I could just add the electrolyte and start storing away. A 1,000 or 500 amp-hour system @ 12V would be nice, using 50 amp-hour modules stacked.

    • JW Smythe

      Don’t get too anxious about this “invention”. It’s a grade school “experiment” (i.e., demonstration). Mentioned in the article, it is functionally the same as the “Baghdad Battery” (250 BCE to 200 CE). Changing the iron to steel, and copper to brass, doesn’t really make it different.

      “Steel” is an alloy of iron and carbon. There are a lot of other “steel” metals, like stainless steel (iron + carbon + nickel + chromium)

      “Brass” is an alloy of copper and a large variety of metals. The brass colored brass would be any alloy with 50% or more copper. Brass plumbing should be about 70% copper, 30% zinc.

      There’s a decent chart here, to help understand the basics.

      To the best of my knowledge, it doesn’t actually work very well.

      For your application, you’d probably want to consider AGM batteries. Find someone who can make them, rather than paying the outrageous prices they sell for. Otherwise, any other deep cycle lead/acid battery, and make friends with the guy at a a local battery refurbishing shop.

      You could also look at NiFe (aka Edison) battery. They’re suppose to work well, and basically last forever. I was looking for info on them. There was a place in the US that had been rebuilding the original early 1900s batteries. There was a company in China manufacturing new batteries, but they are a bit expensive to get to the US. A pallet of batteries will always be heavy.

      • Bob

        I still think this looks promising. The function IS NOT the same as Baghdad Battery, just the general construction. You said “Changing the iron to steel, and copper to brass, doesn’t really make it different.” that is true but misses the actual advancement they made, applying anodization. It is the anodization acting as a catalyst that changes the relationship with the electrolyte beyond the base metal’s performance (making the wiki link worthless in this discussion…). Their test is promising because it is almost as simple to make as the Baghdad Battery but the performance is significantly better and theoretically scalable. If this is the case it could open the possibility for viable small scale battery production. Exactly what Aaron Blake is looking for.

        It is the rarity and international trade requirements of lithium ETC that make them expensive and mainly used for small storage. This new approach using common elements is meant for decentralized large scale storage and long term installations.
        But yes, only time will tell if this is a viable approach on the larger scale.

        • JW Smythe

          Do you know what anodization is? It’s just oxidization. That happens spontaneously in air and other fluids. That thin layer is why metals don’t weld themselves to other pieces of the same metal on contact. Do a quick Google search for “cold welding in space”. With an absence of a protective layer (i.e., oxidization, paint, duct tape, etc), metal parts stick

          On aluminum, it makes the pretty finish that protects it. For iron alloys, it’s rust, which isn’t pretty nor strong.

          You have to be careful with papers like this. There is always someone with a world changing breakthrough. The majority of those “too good to be true” breakthroughs don’t survive peer review, and the amazing properties aren’t reproducible.

          I really wish all the amazing papers were as amazing as they sounded. Unfortunately, I can’t even read the whole paper because of the paywall, and the article was written intentionally vague.

          • Bob

            As far as I can tell you probably just a troll. After this post I won’t be feeding you anymore. Don’t bother the internet anymore with your poorly researched claims, misconstrued ideas, flagrant lack of understanding of the topic you claim to be discussing and overall negativity.

            Before touching of anodization. You CAN read the whole paper, you choose not to pay. And yes, this may not end up being viable. But it also may end up being viable but buried by negative nellies like you who assert with vagueness and ambiguity some supposedly “known” reason why this tech isn’t really worthwhile.

            As the saying goes… “The person who says it cannot be done, should not interrupt the person who is doing it”

            Yes, I know what anodization is. And according to your post you don’t. While it is a form of oxidization the surface created by anodization doesn’t not “happen spontaneously in air and other fluids”. It is different is structure and consistency. Oh, and thanks for bringing up how it works on aluminum and iron seeing as we are talking about steel and brass… The structure of the oxides on an anodized surface are influenced by the electrical circuit created with the metal object becoming the anode. This structure remains substantially more open/porous then what you will find from any natural process. This porousness means greater depth, surface area and the ability to accept another substance into that matrix. Usually this is a dye, or corrosion inhibitors. Surfaces that have “just oxidization” do not have the same properties.
            It is methods of changing the properties of the common base natural materials and processes that are exactly what is needed in this kind of developmental science. Even if what they only develop something a tad better then standard lead acid they will have done something wonderful. Because it will be made out of less toxic, more available materials and could be assembled by the common tinkerer.

  • Murray Foster

    So why is the paper locked up behind a paywall?

  • Michaela Merz

    I think this might be a great discovery. Let’s see the paper and let’s go out and try for ourselves.

  • Pierre Audrit

    Hi all. Maybe a bit ignorant, by why are you publishing this wonderfull research on ACS (40$ to get your paper) if you want to be joined by the makers?

  • Chimp1

    It is a 20Wh/kg battery, like lead acid… Li-Ion is more than 100Wh/kg.

    • Spirit of 76

      I don’t think they intend for this to power laptops, smartphones or electric cars. But arrays of these batteries could conceivably come in useful for storing electricity from solar or wind turbine sources in homes or maybe even at utility scale, given how common and nontoxic the materials are.

    • Lead acid is 40wh/kg

    • h4nd

      True, but work out the $/Wh for a house installation, and you may see the point.

  • Grant Morgan

    Also wonder why not published in open access journal if “When our aim was to produce the materials used in batteries from household supplies in a manner so cheaply that large-scale manufacturing facilities don’t make any sense, we had to approach this differently than we normally would in the research lab,”

  • Cary

    Very much appreciate all of the interest in this work! A few answers to questions on here:
    (1) the technical paper is behind a paywall. Unfortunately, this is how technical publishing works unless the research team pays a huge chunk of money to make the study open access, (not an option in this case). One option to access it is through a local University – since all Universities should have access to ACS journals. I’m trying to keep up with sending reprints to those who ask, but am currently a bit overloaded. The technical paper is geared to researchers with a background in batteries since the strength of our study are the technical achievements that allowed processing of brass and steel into battery electrodes with great performance – something that hasn’t ever been done before.
    (2) we are planning on releasing a video and putting up a small website on this project in coming weeks. There is still quite some design work in translating this achievement from powering an LED to powering a house. We would hope to keep this information updated on the site so that an average DIYer would be able to follow along without the technical jargon that provides a barrier between the research crowd and the public in normal communication media such as technical papers. There is no reason for us to keep any information from the public on this, and actually aim to engage the public to accelerate efforts. In parallel, we will also be striving to develop even more benign methods for material processing since, as some people have pointed out, some household chemicals are still not extremely safe. There will be a forum for thoughts and ideas from the community on this site, and I should have that up by the end of the year.
    (3) A brief technical note: the enabling feature to this work is the ability to process a multicomponent bulk metal to leave behind a (nanostructured) metal oxide that functions as a battery electrode. Prior methods either use highly precise materials that are expensive, or those routes historically developed by Edison and others rely on bulk materials that are not processed. The processing is the critical step to enable the fast charging/discharging, the stable cycling, and the good utilization of the material for energy storage – all three of which would not be possible without our current (ongoing) research. Thank you!

    The vision of this project is inspired by the enormous challenge of energy sustainability in an era of renewable energy generation that is inevitable and will impact all of us and our children. Energy storage is the pivot point for renewable energy harvesting. When the stakes are so high for a solution to this challenge, why would we restrict ourselves to not thinking about directions that may be considered “unconventional?” My ongoing aim in this effort is to break down the language barrier separating the research laboratory and the general public and provide an open and publically available platform to work together and solve this challenge. The caveat is that I am doing all of this in my “spare time” since we do not have direct research funding to address this challenge (hence, please be patient as I get this up and running), and this vision stems from our research advance that gives some substance to this vision. This may not be the ultimate solution to a sustainable future, but it could be (a concept I won’t ignore) – and if we could predict the impact of systems and technologies years before their time there would be no such thing as “innovation.”

    • tbraga14

      Hi Mr. Pint, I’ve subscribed to Vanderbilt Youtube channel and I’m looking forward to your diy video (if it will be posted there, in case of posting in another channel, please reply). Thank you for your great work! Love recycling and experimenting and I’m already thinking in build my own ultrasonic cleaner for this project

    • Zero

      I too have subscribed and will be making a DIY How To video for my 45,000 YouTube subscribers as soon as your information becomes available. This is an enabling technology that must get as much attention as possible, into the hands of the people! Would love to collaborate with you on this project. I may be contacted via my YouTube Channel “ZeroFossilFuel” or web site

      Mark Brasche
      aka: Zero

    • A. J. Tarnas

      Keep up the good work. There’s considerable interest in DIY batteries of every kind, especially chemistries that are comparable to the specific power of lead-acid but are refurbishable and/or made from cheap scrap. You’d do the world a huge service by bringing your steel-brass idea to maturity.

  • cmteuffel

    Don’t know why my last post was removed by vanderbilt, but lets suppose
    it was accidential. The supplement with all the practical details is
    available for free from: