Why China could dominate the next big advance in batteries

China is far ahead of the rest of the world in the development of batteries that use sodium, which are starting to compete with ubiquitous lithium power cells

By Keith Bradsher

In Changsha, deep in China’s interior, thousands of chemists, engineers and manufacturing workers are shaping the future of batteries.

The city’s Central South University churns out the graduates who are advancing the technology, much as Stanford University moulded the careers of Silicon Valley entrepreneurs who pioneered microchips. Across the Xiang River, vast factories mix minerals into the highly processed compounds that make rechargeable batteries possible.

These batteries, mostly made of lithium, have powered the rise of cell phones and other consumer electronics. They are transforming the auto industry and could soon start doing the same for solar panels and wind turbines crucial in the fight against climate change. China dominates their chemical refining and production.

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Now China is positioning itself to command the next big innovation in rechargeable batteries: replacing lithium with sodium, a far cheaper and more abundant material.

Sodium, found all over the world as part of salt, sells for 1 to 3 per cent of the price of lithium and is chemically very similar. Recent breakthroughs mean that sodium batteries can now be recharged daily for years, chipping away at a key advantage of lithium batteries. The energy capacity of sodium batteries has also increased.

And sodium batteries come with a big advantage: They keep almost all of their charge when temperatures fall far below freezing, something lithium batteries typically do not do.

In Changsha, graduates from Central South University’s leafy campus are working on sodium battery technology at nearby research laboratories run by companies including Germany’s BASF, the world’s biggest chemical maker. One of the first large factories for sodium battery chemicals is already under construction a few blocks away from the labs.

Chinese battery executives said in interviews that they have figured out in the past year how to make sodium battery cells so similar to lithium ones that they can be made with the same equipment. Chinese giant CATL, the world’s largest manufacturer of electric car batteries, says it has discovered a way to use sodium cells and lithium cells in a single electric car’s battery pack, combining the low cost and weather resistance of sodium cells with the extended range of lithium cells. The company says it is now prepared to mass produce these mixed battery packs.

“We are ready to industrialise it,” Huang Qisen, the deputy dean of CATL’s research institute, said in an interview at the company’s headquarters in Ningde, China. CATL, which is short for Contemporary Amperex Technology, relies partly on chemicals from Changsha and recently built its first large-scale sodium battery assembly line in Ningde.

Multinational corporations are taking notice of sodium. Research into using sodium for batteries began in earnest in the 1970s, led then by the US. Japanese researchers made crucial advances a dozen years ago. Chinese companies have since taken the lead in commercialising the technology.

Out of 20 sodium battery factories now planned or already under construction around the world, 16 are in China, according to Benchmark Minerals, a consulting firm. In two years, China will have nearly 95 per cent of the world’s capacity to make sodium batteries. Lithium battery production will still dwarf sodium battery output at that point, Benchmark predicts, but advances in sodium are accelerating.

At next week’s Shanghai auto show, carmakers and battery producers are expected to announce plans for sodium batteries in at least some limited-range subcompact cars for the Chinese market.

The most immediately promising use for sodium batteries is for electric grids, the networks of wires and towers that transmit electricity. Batteries for grids are a fast-growing market, especially in China. Tesla said this week that it would build a factory in
Shanghai to make lithium batteries for energy providers.

Sodium batteries need to be bigger than lithium ones to hold the same electrical charge. That is a problem for cars, which have limited space, but not for electricity grid storage. Utilities that switch from lithium to sodium can simply put twice as many big batteries in an empty lot near solar panels or wind turbines. Utilities around the world have an increasing appetite for massive amounts of battery storage as they move to climate-friendly sources like solar and wind. They need to be able to store energy while the sun shines and the wind blows, and then use it later as a replacement for electricity powered by coal or gas.

Electricity in one large Chinese province, Shandong, already sells for up to 20 times more in early evening, when demand is high, than at mid-day, when the grid is flooded with more solar power than factories and homes need. The power generation companies use lithium batteries to distribute their renewable electricity across more hours.

But some utilities, like Three Gorges Corporation in west-central China, are beginning to experiment with sodium batteries. Many provinces have begun requiring newly built solar or wind power farms to install enough batteries to store 10 to 20 per cent of the electricity that they generate, said Frank Haugwitz, a consultant who specialises in China’s solar industry.

CATL has installed lithium batteries the size of minivans at electric car charging stations in cities like Fuzhou. The batteries automatically charge whenever electricity is cheap, like overnight or when the sun is shining on the charging station’s rooftop solar panels, and are ready whenever motorists drive up to recharge. CATL is studying whether sodium can be used in such locations.

Unlike lithium batteries, the latest sodium batteries do not require scarce materials like cobalt or nickel. Yet as China races toward leadership in sodium, it still faces challenges. For starters, there is where to get the sodium.

While salt is abundant, the US accounts for over 90 per cent of the world’s readily mined reserves for soda ash, the main industrial source of sodium. With minimal natural reserves of soda ash and a reluctance to rely on imports from the US, China instead produces synthetic soda ash at chemical plants fueled by coal, which has a record of hazardous water pollution. Another question hanging over sodium is whether lithium will remain costly. Lithium prices quadrupled from 2017 to last November, but have since dropped by two-thirds. There are also doubts about the durability of sodium batteries. Power companies want to see how they perform for years outdoors, not just in labs, said David Fishman, a power sector consultant at Lantau Group, a consulting firm.