Alternative lithium battery? Sodium battery needs to "pass through" a long tunnel

As we all know, lithium ion is an active ingredient in cell phones, laptop computers and car batteries. But given the high cost of lithium, researchers have been looking for another, more abundant element to replace it.

Subsequently, some start-up companies and established companies saw sodium ions as an active ingredient to develop rechargeable batteries. Sodium is a “neighbor” of lithium on the periodic table.

In addition to the availability of sodium, it has several other important properties - the most important of which is its fire resistance. "Of course, it can also store energy comparable to a lithium battery, which is a good choice," said Minah Lee of Stanford University who researched sodium batteries.

Today, many companies are developing sodium batteries whose ultimate goal is to replace lithium batteries. CNRS recently announced the establishment of Tiamat, a startup company based in Amiens, which will develop sodium batteries and market them by 2020. CNRS said it will be designed to be a size model like the 18650.

There is also an American startup called Aquion, which focuses on the storage of high-capacity seawater batteries. Bill Gates and Kleiner Perkins initially invested $190 million in it. However, the company's subsequent development even embarked on the dilemma of bankruptcy. In July, JulineTitansLCC acquired it for $9.16 million.

At the same time, some university researchers are now focusing on replacing lithium in the battery with sodium. The advantage of scientists is that they can use large instruments (such as accelerators) to study anode materials and their functions.

"We can clearly understand the whereabouts of sodium, whether it is at the subtle atomic level (how it binds to other atoms) or at a more macroscopic level, and the changes it produces when electrode particles absorb sodium." Stanford University responsible SLAC Michael Toney, a researcher at the National Accelerator Laboratory, is one of them.

However, at a time when academics and companies are making research attempts, power companies and automotive power system manufacturers are not very good at recognizing sodium batteries. They are more willing to insist on using lithium batteries. “The current cost of lithium-ion battery technology is very competitive in a variety of markets,” explains David Snydacker, battery expert at Dosima Research. “So, for a new sodium battery to succeed, it must not only compete with traditional technologies, it must also Competing with lithium batteries is a very high requirement."

An unsolved problem with sodium batteries is finding or creating a high-capacity anode, the negative electrode of a battery. One of the more desirable materials is hard carbon, which allows the storage of sodium ions in the space between atoms. "Lithium-ion batteries use graphite, but that doesn't apply to sodium ions," Toney said. "But we use hard carbon. Although this is not optimal, no one really understands this material."

Scalability is an important feature of hard carbon. "We can readjust batteries of different sizes. The focus of this electrode material is its sustainability. It is based on biomass, so if you use more, you can use it for everything," said Lee.

In order to seek market recognition, another decisive factor is the use of existing industrial production lines to produce sodium batteries. "The handling of sodium batteries should be very similar to that of lithium-ion batteries."

Therefore, the sodium battery may be born from the existing production line, but the problem is to wait until when? One idea is that sodium batteries are actually very economical, but this view is still inconclusive.

Although researchers related to Tiamat have already put 2020 into production as a deadline, it remains to be seen whether they will achieve this goal. Mathieu Morcrette of the University of Amiens, France, admits, “There is still a lot of work to do. We have not yet reached our goal.”

In addition, the statement that sodium is cheaper than lithium is not at the very beginning at the beginning. Snydacker said: "The price of sodium is indeed cheaper than lithium. Without using lithium, the cost can be reduced by 5% to 10%, but the remaining cost will be quite expensive. But he is optimistic about the future.

"For sodium battery technology, there will be a bright light at the end of a long tunnel," he said. "Once all investment is in place, there will be a quality product with reasonable prices. The main challenge for new battery technology is not Manufacturing processes are difficult to develop and build, but compared to those that have been thoroughly studied and polished, new battery technologies are fundamentally not superior either in performance or cost."