New low-cost battery could help store wind, solar energy

Researchers are developing a new battery, using low-cost materials such as sodium and magnesium, that could make storing power from renewable sources such as wind and solar energy more affordable.
Wind and solar energy projects are growing at a respectable pace. But storing electric power for days when the air is still or when the Sun goes down remains a challenge, largely due to cost, researchers said.
Today, lithium-ion batteries are the storage technology of choice for many applications, from electric cars to smartphones.
A luxury electric cars maker is ambitiously expanding its lithium-ion technology and has already started rolling out systems to homeowners in a pilot project to save up power for homes, researchers said.

However, the USD 3,000 price tag for the pack itself plus installation costs put it out of reach for most customers.
To make larger-scale energy storage more accessible, Maksym V Kovalenko from ETH Zurich in Switzerland and colleagues wanted to develop an affordable alternative to lithium-ion.

The researchers started with magnesium as the battery's safe, inexpensive and high-energy density anode material and paired it with pyrite, which is made of iron and sulphur, as the cathode.
The electrolyte - the electrically conducting component - contains sodium and magnesium ions.
Testing showed that the resulting device's energy density was close to that of lithium-ion batteries.

It could get an additional two- to three-fold boost with further development of magnesium electrolytes.
Since it is made with low-cost materials, it could one day help support grid-scale energy storage, researchers said.
The study was published in the journal Chemistry of Materials.