“Unthinkable” Energy Storage Combo Leverages Fool’s Gold
The energy storage field could be in for a transformation if a team of researchers from Switzerland is on the right track. They’re hot on the trail of a battery deploying the humble crystalline material fool’s gold — aka iron pyrite — with the aim of pulling off a twofer. The new pyrite battery would enable low-cost, large-scale energy storage at power plants and other facilities, thus freeing up global supplies of lithium for small-scale use, including electric vehicle batteries.
Lithium supply is a key issue for the growing EV and stationary energy storage markets. Though lithium-ion battery technology is a proven and efficient solution, as these markets grow, the cost of lithium could surge, so the hunt is on for cheaper, more abundant materials to take over.
From Geological Joke To Energy Storage Hero
Iron pyrite is a common sulfide material easily mistaken for gold by the uninitiated due to its yellowish appearance. Pyrite has many industrial applications, and the US battery company Energizer is apparently the first to use pyrite in a single-use consumer battery in tandem with lithium.
Deploying pyrite in rechargeable batteries presents a different set of challenges, and that’s the task undertaken by Switzerland’s Laboratory for Thin Films and Photovoltaics at the leading research institution Empa (Empa is the German acronym for Swiss Federal Laboratories for Materials Science and Technology).
Dubbed “unthinkable” by Empa’s press office, the new energy storage solution consists of a magnesium anode and a cathode made of pyrite nanocrystals, with an electrolyte of magnesium and sodium ions.
Here’s the rundown from Empa:
The sodium ions from the electrolyte migrate to the cathode during discharging. When the battery is recharged, the pyrite re-releases the sodium ions. This so-called sodium-magnesium hybrid battery already works in the lab and has several advantages: The magnesium as the anode is far safer than highly flammable lithium. And the test battery in the lab already withstood 40 charging and discharging cycles without compromising its performance, calling for further optimization.
As Empa notes, all of the materials used in the new battery — iron, magnesium, sodium, and sulfur — are among the most abundant on Earth’s crust by mass, ranging from 4th to 15th place. In contrast, lithium clocks in around number 33.
That doesn’t sound too bad, but consider that fully half of the world’s known lithium reserves are concentrated in Bolivia and the supply chain begins to look a little dicey.
Here in the US, the Obama Administration has been eyeballing just such supply chain issues related to renewable energy and energy storage. In 2013, the Administration launched the Critical Materials Institute under the Energy Department to address supply chain bottlenecks, including the development of abundant, low-cost substitutes for lithium (that includes using iron pyrite for solar cells, btw).