An Australian team is looking to commercialize a large-scale sodium battery technology, despite the chemistry’s long and checkered history. 

Researchers at the University of Wollongong (UOW), New South Wales, are developing a 5-kilowatt-hour sodium-ion battery pack that can be used for stationary storage applications, according to the Australian Renewable Energy Agency (ARENA).

A 30-kilowatt-hour battery system is due to be tested alongside solar panels at a Sydney Water sewage pumping station in 2019, said ARENA, which has put AUD $2.7 million (USD $2.1 million) into developing the technology. 

Before then, a single 5-kilowatt-hour battery will debut in a UOW sustainable home showcase called the Illawarra Flame House. ARENA’s funding, part of a total project cost of AUD $10.6 million (USD $8.1 million), was announced in April 2016. 

At the time, ARENA CEO Ivor Frischknecht called it “a new type of sodium battery that’s modular. The idea is very low-cost storage.”

The agency also said the research is aiming to create a viable alternative to lithium-ion battery chemistries, which face supply-chain concerns.

“This project will develop a new sodium-ion battery architecture, optimized for use in renewables storage applications, by building on the world-class energy materials research and deep industry ties of the Institute for Superconducting and Electronic Materials,” wrote the agency in a blog post.

But sodium-based batteries have been around for decades. And their success has been patchy, to say the least.

The saltwater battery maker Aquion crashed out of the market in March after burning through roughly $190 million in venture capital. It returned under new ownership in July

Before its collapse, Aquion had attracted praise for its environmentally friendly and potentially low-cost batteries. The company blamed the "extremely complex, time-consuming, and very capital-intensive" process of creating a new electrochemistry.

But it was not the first sodium battery maker to run into problems. In 2015, the digital industrial giant General Electric put the brakes on production of a sodium-ion product called Durathon, which it had bought via a U.K. startup called Beta Research in 2007.

Sodium-based batteries have been relatively successful in other areas. Italy’s FZSoNick (formerly FIAMM), for example, produces sodium-nickel batteries for stationary storage and electric vehicles.

Japanese automotive parts maker NGK, meanwhile, is commercializing a sodium-sulfur battery that has been deployed at scale in projects such as a 34-megawatt, 245-megawatt-hour hybrid wind and storage system in Aomori, Japan.  

In Italy, the transmission system operator Terna “has significant capacity” of sodium-sulfur batteries, installed in 2014 and 2015, according to Valts Grintals, an analyst at Delta Energy & Environment.

Overall, though, “it is still a very small part of the market, and in the past two years there has not been [a lot of] interest in this chemistry,” he said.

Today’s sodium batteries can be divided into high-temperature products, which offer high energy capacity and long duration, and low-temperature variants, which are smaller, safer and potentially cheaper.

But both have drawbacks in terms of cost, efficiency and cycling capability, said Grintals. High-temperature batteries also suffer from flammability issues. Furthermore, sodium-based batteries are suffering as customers stampede toward lithium-ion.  

As of mid-2017, International Renewable Energy Agency figures showed sodium-sulfur and other sodium-based batteries making up 3 percent and 8 percent, respectively, of the global electrochemical storage market. Lithium-ion, in contrast, represented 59 percent.

“Scarcity of lithium, which is one of the big selling points from a sodium-ion perspective, is not an issue that the industry is too concerned with yet,” Grintals said. “Based on how the market looks, this will not be a driver for uptake of sodium tech.”

The Australian team could face an uphill struggle with sodium-based batteries even if its concept overcomes the drawbacks of previous concoctions. “When it comes to products like the one from Aquion, it has been a tough sell,” said Grintals.

“I don’t see anything in the market indicating that this could change in the future.”