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Why making lighter and better batteries takes time
Chinese car manufacturers aren’t the only ones trying to develop new types of batteries. In Norwegian laboratories, new materials are being tested to make batteries lighter, cheaper, and more environmentally friendly.
Lithium-ion batteries have revolutionised our lives since they first came onto the market in the early 1990s.
They are now used in all sorts of things, such as mobile phones, laptops, and electric cars.
But lithium-ion batteries are still heavy, their range could always be improved, and they can pose a significant fire risk if damaged.
Their production also requires large quantities of metals such as mined nickel and cobalt from mining operations that pose ethical and environmental challenges.
The material has a large environmental footprint
Lithium is an expensive material, and its extraction process has a significant environmental impact.
Despite all this, lithium-ion batteries are still used in virtually all electric cars. So why is it taking so long to develop better alternatives?
“When all is said and done, battery development has actually progressed quite rapidly. The first lithium-ion batteries were introduced in 1991 and were the result of 20 to 25 years of intensive research. And this research is still ongoing,” says Ann Mari Svensson.
She is a professor at NTNU’s Department of Materials Science and Engineering.
In the lab in NTNU's old chemistry building, researchers make their own batteries. From scratch. Battery research involves trial and error and is extremely labour-intensive, Svensson explains.
Researchers are testing significantly cheaper materials
“Having worked on lithium-ion batteries for many years, we are now trying to develop batteries that only use aluminium and graphite. These are significantly cheaper than lithium,” says Svensson.
The batteries they make are similar to the ones you put in your TV remote control. They are small coin cells, in which materials can be tested in small quantities.
“We perform the coating process on a small scale, and then we charge and discharge the batteries over and over, sometimes up to a thousand times. We then open them up and see what they look like inside,” says the professor.
The researchers are trying to understand what happens when the batteries charge and discharge, and why they fail.
Using a scanning electron microscope (SEM), they can see whether large amounts of reaction products have accumulated on the surface of the graphite.
"We also perform chemical analyses to identify which bonds and components are present. It's quite the puzzle,” says Svensson.
Some materials are still expensive and heavy
So far, the experiments look promising, but using aluminium as an anode is just one piece of an even bigger puzzle.
Between the cathode and the anode, the researchers use an electrolyte that is still both heavy and expensive.
“For this to be commercially viable, we need to find new electrolytes, and that's incredibly difficult. To achieve this, we need to combine trial and error with fundamental modelling,” says the professor.
Fundamental modelling refers to building a simplified representation of a system, process, or reality using fundamental principles, mathematical equations, or laws of physics.
Trial, error, and modelling
It is really difficult to get all the materials that need to be part of a battery to work well together.
“You might have an effective anode that works with a specific electrolyte, but then you have trouble finding a compatible cathode. On top of that, it has to be inexpensive, thermally stable, and it must not catch fire. It also needs to be lightweight and suitable for large-scale production. The batteries must be able to be recharged frequently and have the correct voltage,” says Svensson.
Researchers also get some help from molecular dynamics simulations.
This is a method in which computers are used to simulate how atoms and molecules move over time.
“But even these models have their shortcomings. They can only make fairly limited predictions. We're simply unable to design a battery from scratch,” the researcher says.
Not everything has to happen in Asia
One alternative to lithium-ion batteries that is ready to be used on roads around the world is sodium-ion batteries.
Sodium is readily available and is commonly used in household products such as table salt and baking soda.
“Replacing lithium with sodium has taken place fairly quickly. The result is a type of battery that's somewhat similar to lithium-ion batteries but a little heavier,” says Svensson.
The first Chinese cars equipped with sodium-ion batteries have already been made.
At SINTEF Energy, researcher Fride Vullum-Bruer is keen to strengthen Norwegian research and industry in the field of battery development. Not everything has to take place in Asia.
The automotive industry leads the research
“There have been so many incredible advancements in battery technology. When the automotive industry really started to catch on to the idea of electric cars, it was the Asian countries in particular that threw their full weight behind the development. China led the way, along with South Korea and Japan,” says Vullum-Bruer.
As a result, it is primarily the automotive industry that has pioneered this research.
Vullum-Bruer believes that funding for battery research in Norway needs to improve if the country is to keep up.
“There has been a significant decline in funding for energy research in general, not just battery research, over the past decade. At the same time, competition has increased, meaning the funding is spread more thinly,” she says.
Norway leads in the maritime sector
When it comes to batteries for the maritime sector, however, Norway is at the forefront. This has led companies such as Siemens Energy and Corvus Energy to establish production facilities in Norway.
“Norway is a world leader in the shipping industry, especially in the field of electric ferries. The rest of the world looks to us in that area,” says Vullum-Bruer.
A boat that is just cruising leisurely across a fjord can get by with heavier but more affordable batteries than a sports car that needs to accelerate from 0 to 100 kilometres per hour in a matter of seconds.
Development is moving towards different types of batteries depending on how they will be used.
Batteries are becoming increasingly tailored to specific applications. Initially, cathodes consisted solely of lithium, cobalt, and oxygen (LiCoO2).
"But then it was discovered that adding a small amount of nickel resulted in different properties. Add a little manganese, and you get a different set of properties again. These variations yield differences in voltage level, energy density, stability, and safety. It depends on what properties you want from the battery and what it is going to be used for,” the researcher says.
"So why not just start producing them?"
“Well, batteries are subject to very strict requirements, especially those intended for use in vehicles. It can easily take ten years to get a new concept out on to the market. The process takes several years of testing and verification," says Vullum-Bruer.
She adds that the product also has to be tested by third parties to verify that it lasts as long as claimed and does not suddenly degrade faster than expected.
Different batteries for different uses
The SINTEF researcher personally favours solid-state batteries as the future solution for electric cars. In other words, batteries that use solid electrolytes instead of liquid ones.
“Several Chinese companies have announced that they are going to start mass-producing solid-state batteries. But it will take some time before they become as widespread as other batteries,” Vullum-Bruer says.
Another variant is batteries in which the cathode consists of lithium iron phosphate, known as LFP batteries. They have a slightly lower energy density than NMC batteries, which are based on nickel, manganese, and cobalt.
Lower energy density means that they store less energy per unit of weight or volume. The upside is that they are cheaper and have a significantly longer lifespan, the researcher explains.
It is no longer the case that one size fits all and that lithium-ion batteries are used everywhere.
“We will see other technologies develop. Lithium-ion batteries are not necessarily the best choice for stationary energy storage, such as in power plants or solar power facilities, or in small, lightweight vehicles with a short range," she says.
If there are no weight or volume restrictions, other technologies can be used that are safer and work just as well for the intended purpose, the researcher explains.
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Read the Norwegian version of this article on forskning.no
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