In Changsha, deep in the interior of China, thousands of chemists, engineers and manufacturing workers are shaping the future of batteries.
The city’s Central South University pushes out the graduates who advance technology, just as Stanford University shaped the careers of Silicon Valley entrepreneurs who pioneered microchips. Across the Xiang River, huge factories blend minerals into the highly processed compounds that make rechargeable batteries possible.
These batteries, usually made of lithium, have fueled the rise of cell phones and other consumer electronics. They are transforming the automotive industry and could soon do the same for solar panels and wind turbines, which are crucial in the fight against climate change. China dominates their chemical refining and manufacturing.
Now China is positioning itself to master the next big innovation in rechargeable batteries: replacing lithium with sodium, a much cheaper and more abundant material.
Sodium, which is found around the world as part of salt, is sold for 1 to 3 percent of the price of lithium and is chemically very similar. Recent breakthroughs mean that sodium batteries can now be charged daily for years, negating a key advantage of lithium batteries. The energy capacity of sodium batteries has also increased.
And sodium batteries have a big advantage: they retain almost all of their charge when the temperature drops well below freezing, something lithium batteries typically don’t do.
In Changsha, graduates of Central South University’s leafy campus work on sodium battery technology in nearby research laboratories run by, among others, Germany’s BASF, the world’s largest chemical manufacturer. One of the first major sodium battery chemical plants is already under construction, a few blocks from the laboratories.
Chinese battery managers said in interviews that over the past year they have discovered how to make sodium battery cells so similar to lithium batteries that they can be made with the same equipment. Chinese giant CATL, the world’s largest manufacturer of batteries for electric cars, says it has discovered a way to use sodium cells and lithium cells in an electric car battery pack, combining the low cost and weather resistance of sodium cells with its extensive range lithium cells. The company says it is now ready to mass-produce these mixed battery packs.
“We are ready to industrialize it,” Huang Qisen, the deputy dean of CATL’s research institute, said in an interview at the company’s headquarters in Ningde, China. CATL, short for Contemporary Amperex Technology Ltd., partly relies on chemicals from Changsha and recently built its first large-scale sodium battery assembly line in Ningde.
The rise of electric vehicles
Multinational corporations are taking note of sodium.
“It will take away the spike in demand for lithium,” said Mike Henry, the CEO of BHP, the world’s largest mining company. “I am convinced that sodium will replace lithium for certain applications.”
Research into using sodium for batteries began in earnest in the 1970s, then led by the United States. Japanese researchers made crucial progress ten years ago. Chinese companies have since led the way in commercializing the technology.
Of the 20 sodium battery plants now planned or already under construction around the world, 16 are in China, according to consultancy Benchmark Minerals. In two years, China will have nearly 95 percent of the world’s capacity to make sodium batteries. Lithium battery production will still dwarf sodium battery output at that point, Benchmark predicts, but progress in sodium is accelerating.
At next week’s Shanghai auto show, automakers and battery makers are expected to announce plans for sodium batteries in at least some limited-range subcompact cars for the Chinese market.
The most promising use for sodium batteries is for power grids, the networks of wires and towers that transmit electricity. Batteries for power grids are a fast-growing market, especially in China. Tesla said this week it will build a factory in Shanghai to make lithium batteries for energy suppliers.
Sodium batteries must be larger than lithium batteries to hold the same electrical charge. That’s a problem for cars, which have limited space, but not for grid electricity storage. Utilities switching from lithium to sodium can simply put twice as many large batteries in an empty spot near solar panels or wind turbines.
Utilities around the world are increasingly in need of massive amounts of battery storage as they transition to climate-friendly sources like solar and wind. They need to be able to store energy when the sun is shining and the wind is blowing, and use it later as a replacement for coal or gas electricity.
Electricity in a major Chinese province, Shandong, is already selling up to 20 times more in the early evening, when demand is high, than by mid-day, when the grid is flooded with more solar energy than factories and homes need. The power generation companies use lithium batteries to distribute their renewable electricity over more hours.
But some utilities, such as Three Gorges Corporation in West Central China, are starting to experiment with sodium batteries. Many provinces have begun requiring newly built solar or wind farms to install enough batteries to store 10 to 20 percent of the electricity generated, said Frank Haugwitz, a consultant specializing in China’s solar industry.
CATL has installed minivan-sized lithium batteries at electric car charging stations in cities like Fuzhou. The batteries charge automatically when electricity is cheap, such as at night or when the sun shines on the solar panels on the roof of the charging station, and are ready when motorists drive up to charge. CATL is investigating whether sodium can be used in such locations.
Unlike lithium batteries, the latest sodium batteries don’t require scarce materials such as cobalt, a mineral mined primarily in Africa under conditions that have alarmed human rights groups. The latest sodium batteries also do not require nickel, which comes mainly from mines in Indonesia, Russia and the Philippines.
But as China races towards leadership in sodium, it still faces challenges. For starters, there’s where to get the sodium.
While salt is abundant, the United States accounts for more than 90 percent of the world’s readily mined reserves of soda ash, the main industrial source of sodium. Deep beneath Wyoming’s southwestern desert lies a vast deposit of soda ash, formed 50 million years ago. Sodium carbonate has long been mined there for the American glass industry.
With minimal natural reserves of soda ash and a reluctance to rely on imports from the United States, China instead produces synthetic soda ash in coal-fired chemical plants.
China’s synthetic soda ash industry has a record of dangerous water contamination. That includes the collapse of a pile of alkali slag in east-central China in 2016 that washed away cars and polluted a major river. The country’s environmental agency is working to clean up the industry.
Another question hanging over sodium is whether lithium will remain expensive. Lithium prices quadrupled from 2017 to last November, but have since fallen by two-thirds.
There are also doubts about the durability of sodium batteries. Energy companies want to see how sodium batteries perform for years outdoors, not just in laboratories, said David Fishman, an energy industry advisor at Lantau Group, a consulting firm.
But Mr. Fishman and others are now watching closely the development of sodium batteries. Demand for batteries is growing rapidly and lithium is unlikely to remain the dominant material indefinitely.
“Yes, sodium plays a role,” said BHP’s Mr. Henry. “China is at the forefront of this in encouraging research.”
Li you contributed research.
