This 'junkyard' battery design from a Vanderbilt University research team lays the groundwork for DIY batteries for homes.
A new battery design using two of the most commonly scrapped metals, brass and steel, altered with a common household chemical, could eventually lead to a revolution in home-brewed battery storage construction, as this battery has been shown to have a long lifecycle and "ultrafast" charging and discharging cycles.
A team of researchers at Vanderbilt University has created a "world's first" of its kind steel-brass battery using scrap metals, which has been shown to be able to store energy "at levels comparable to lead-acid batteries" yet with charging and discharging rates that are on par with supercapacitors, which offer "ultrafast" rates of energy transfer. This new battery design, while not yet built as a full-scale prototype, could offer a significant advantage over both conventional lead-acid batteries and the current leader in the sector, lithium-ion cells, due to its non-flammable electrolyte liquid, which uses potassium hydroxide, a low-cost salt commonly found in laundry detergent, and its DIY-friendliness.
"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." - Cary Pint, Vanderbilt University assistant professor of mechanical engineering
According to Vanderbilt, the key to the high performance of this steel-brass battery is anodization, which restructures the surface of the metals into "nanometer-sized networks of metal oxide" that react with the electrolyte to store and release energy. The team anodized scraps of brass and steel with "a common household chemical" and household electricity in a room-temperature process, which allowed for varying sizes and shapes of metal scraps (including screws and shavings) to be converted into functional battery electrodes.
"The simplicity of this approach, building from chemicals commonly available in a household, enables a simple pathway to the local recovery, processing, and assembly of storage systems based on materials that would otherwise be discarded." - ACS Energy Letters
The new steel-brass battery, which was measured with cell voltages up to 1.8V and an energy density up to 20Wh/kg, was tested for 5,000 consecutive charging cycles (said to be equal to some 13 years of daily charging), and retained more than 90% of its capacity.
"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." - Pint
Holy homemade battery storage, Batman!
A design that repurposes common scrap metals into a high performance battery using common chemicals and a room temperature process, incorporating a stable and low-cost electrolyte,, with a lifecycle of over 5000 cycles, and "ultrafast" charging rates? Sounds like the recipe for a home battery revolution to me, not to mention the implications for DIY energy storage for off-grid and developing world communities.
The team published its research in the journal ACS Energy Letters under the title "From the Junkyard to the Power Grid: Ambient Processing of Scrap Metals into Nanostructured Electrodes for Ultrafast Rechargeable Batteries."