Renewable energy storage advances with sodium ion success

With the climate clock ticking, many researchers across the globe have been working on more sustainable, more efficient batteries needed to make the transition to renewable energy a reality. Scientists in the United States, and now China, are among those making some progress.

The latest claim comes from Contemporary Amperex Technology Co., Ltd. (CATL), which operates four research and development centers in China. They’ve been working on an elusive success with a sodium-ion battery for years, for electric vehicles (EV) and other applications, but recently announced they’re ready to start production and build out supply chains by 2023.

CATL says the sodium-ion battery works much like lithium batteries do, but sodium has always had special challenges because of its chemical properties. It’s been harder to develop sodium ion batteries that hold their charge and maintain a good range, while working well and safely across a longer lifespan.

That’s been a barrier to making sodium ion batteries available; most of them are still made with lithium and cobalt. The problem with the use of these rare minerals is, among other things, the climate impact in places as diverse as Ecuador and the Democratic Republic of Congo. They’re also likely to be in short supply by 2050, according to some analysts, while the earth’s sodium resources remain plentiful.

A 2019 World Economic Forum report called for development of more sustainable batteries by 2030, with a target of reducing greenhouse gas-intensity of the battery value chain by 45% at the same time.

That’s highlighted the need for what so many scientists are working on. In the United States, researchers from Washington State University (WSU) and Pacific Northwest National Laboratory (PNNL) announced some success last year with a sodium-ion battery that works as well as some lithium models. Their research, led by WSU professor Yuehe Lin and senior researcher Xiaolin Li at PNNL, was published in the journal ACS Energy Letters.

“This is a major development for sodium-ion batteries,” said Dr. Imre Gyuk, head of the energy storage program for the U.S. Department of Energy that supported the work at PNNL. “There is great interest around the potential for replacing Li-ion batteries with Na-ion in many applications.”

The WSU researchers point out that using sodium ion instead of lithium ion batteries goes beyond replacing them in EVs. That’s going to drive demand in coming years, which causes its own set of climate impacts, but the real gains in using sodium ion batteries are found in the power grid in the wider transition to carbon-free energy.

CATL says its first-generation sodium ion batteries are designed for transport, and their product is a hybrid that uses both sodium and lithium. Dr. Qisen Huang, head of the CATL Research Institute, said the same equipment and facilities used to make lithium batteries can be used to make the new sodium-ion batteries too.

But CATL also has an eye on battery storage for the power grid. It runs a 100 MWh energy storage power station in Jinjiang, as part of a pilot project with China’s National Energy Administration. It’s the first such grid storage facility in the country and just began operation last year. In July, a second effort was launched and moved the needle from 100 MWh to 600 MWh.

“As of July 1, 2021, the (Jinjiang) station has been operated safely for 535 days, with a total energy discharge of 68.52 GWh,” says CATL. That’s equal to annual energy consumption for more than 150,000 households, assuming a use of 3,000 kWh for a three-person family. And—as with other advances in battery storage—it’s a cause for real optimism about the planet’s energy transition.