Working in the drying room of Deakin University’s Battery Research and Innovation Hub is not a day at the beach.
“[It’s] It’s more like a desert than a beach,” says General Manager Dr. Timothy Koo. “At the beach, at least the moisture comes in.”
150 meters2 The dry room is Australia’s largest research facility that Khoo knows of, and is essential for prototyping and testing next-generation batteries.
“It’s very difficult to work there for long hours,” Koo said. “It’s not dangerous, but your eyes and skin will start to dry out and you’ll feel like you’ve been outside in the sun all summer.”
The room must be dry, as water, moisture, and humidity are deadly to batteries during manufacturing. According to Khoo, contamination means it may not work or its performance may be compromised.
Depending on the material, it may be dangerous in the worst case scenario.
“Lithium does not easily react with water,” Koo says. “I don’t know if you ever did science in high school, but it’s in the same category of chemicals as sodium and potassium. If you’ve ever thrown sodium into water, it explodes. This is a similar reaction for lithium metal.”
The center is booming as companies race to develop next-generation battery technology.
Most people are familiar with lithium-ion batteries, which were first commercialized by Sony in the 1990s to power portable music players. From those humble beginnings, rechargeable lithium-ion batteries are now king, powering cell phones, laptops, and, in the most high-end applications, electric cars.
One McKinsey analysis It is suggested that the global lithium-ion battery market will grow into a $400 billion industry by 2030. But lithium-ion technology is well understood, and those seeking change are increasingly turning to solid-state batteries.
hype and hope
Dr. Rory McNulty, senior analyst at Benchmark Minerals Intelligence, says the hype around solid-state batteries has been growing since the first commercial solid-state batteries were introduced by French company Blue Solutions in 2015.
The company’s batteries were designed for use in electric buses, but had design limitations that required charging times of more than four hours. This shows how difficult the development process is, even for a company like Toyota.
Last July, the global auto giant announced a breakthrough in the development of solid-state batteries, claiming it would cut their manufacturing size, weight and cost in half.
This was met with both excitement and skepticism, as Toyota has poured money into developing solid-state batteries since 2006 and has been reluctant to produce fully electric vehicles for the past decade.
This development was quickly followed by another in October, Toyota and Japanese oil company Idemitsu said. They aimed to develop and manufacture solid state. The company will develop an electrolyte and bring it to market by 2028.
Toyota is not the only company active in this region. In January, Volkswagen announced that testing of a solid-state battery developed by QuantumScape successfully achieved more than 1,000 charging cycles and maintained 95% of its capacity.
Meanwhile, Chinese companies such as WeLion and Nio EV are partnering to rush production of solid-state batteries by 2024, but Western companies will have to wait until 2024, McNulty says. .
“Toyota has postponed its solid-state delivery schedule several times in recent years, and I think this is a testament to how difficult some of the technical challenges underpinning the development of new technology are.” says.
How the battery works
The fundamental promise of solid-state batteries is to produce more energy in smaller cells. Although several approaches have been taken to develop this technology, Koo said two materials have received the most public attention: silicon and lithium metal.
“Silicon-based negative electrodes are a little more advanced than lithium metal-type batteries in terms of technological preparation,” he says. “From a purely scientific or engineering standpoint, I think lithium metal batteries are a little more innovative.
“That’s if we can get people to work.”
Broadly speaking, there are three components that make up a battery: the cathode, the anode, and the electrolyte. The anode, commonly known as the “negative” side of the battery, emits electrons into the circuit. The positive side, or cathode, receives incoming electrons. Electrolytes allow movement between ions.
The interaction of these components determines the battery’s “energy density,” or the amount of energy it can hold relative to its weight. Batteries with higher density can hold more charge, making them suitable for things like electric cars.
Unlike current lithium-ion batteries, which use a graphite silicon anode with a liquid electrolyte, solid-state batteries, as the name suggests, replace the liquid with a solid material.
This creates a safer battery as there is no risk of fluid leaking if the case is punctured, as in a car accident, and reduces the chance of lithium ignition. More importantly for EV drivers, it promises a significant increase in range.
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However, despite the hype, the development of solid-state batteries has been hampered by negative electrodes.
Dendrites and development
Among several variations, lithium metal anode solid-state batteries have received significant attention as a potential future high-performance battery technology.
catch? In their development, a problem known as “dendriticism” was encountered.
Dendrites are formed when lithium ions are “plated” onto a pure metal anode, leaving small protrusions on the surface.
Lee Finniear, chief executive officer of Li-S Energy and founding director of the Advanced Materials and Battery Council, notes that these defects increase over time, and that “the apex of large-city buildings during lightning strikes is It plays a similar role.” ”
“The lithium ion is trying to find the shortest path to the anode,” he says. “If there is any change or peak on the anode, it tends to attract more ions, which plate out as lithium, causing the peak to rise.”
Depending on how large these dendrites grow, they can break through the material separating the anode and cathode, causing a short circuit.
“And that drains the battery,” he says.
There are other challenges, but solving these problems can be difficult and expensive. That’s why other companies prefer to use silicon anodes, which rely on materials similar to those used in photovoltaic panels.
Due to its high conductivity, it is believed that the more silicon used in the anode, the better its performance.
The silicon anode acts like a sponge that absorbs water, expanding and contracting with each charging cycle. Adding silicon increases the amount of expansion of the anode, and a pure silicon anode can expand up to four times its size.
Without intervention, the anode will eventually shatter on its own.
One modification involves structuring the silicon in a special way, and the other involves finding additives that change its behavior.
Although it is possible to solve these problems, commercializing these batteries for EVs remains difficult.
Future technology will require rebuilding production lines and resolving supply chain issues, especially as no company currently produces lithium metal foil of sufficient purity to supply automotive battery manufacturers. There is.
A breakthrough that addresses these issues and lowers the production costs of solid-state batteries would be revolutionary, but Toyota has so far been cautious about the materials it uses for its negative electrodes.
In response to questions, a Toyota Australia spokesperson said they could not disclose the information because “research and development is carried out by the parent company.”
In any case, industry insiders privately say it’s best to simply assume the company is going after “everything.”
“People forget we’re talking about science here,” Finnier said. “We’re talking about persuading electrons, ions, and chemicals to do what you’re told. That’s not software development, and it’s not something you can program yourself.
“These breakthroughs are very important, but they take a lot of effort.”
