This company says it can make better batteries by using more silicon, and less graphite
Silicon is already being used in lithium-ion batteries in small quantities, but one Australian small cap thinks increasing it may improve battery performance.
Batteries are made up of an anode (positive) and a cathode (negative) and the electrical current flows between the two.
Small amounts of silicon in the anode of the battery improves energy storage by increasing the amount of lithium that graphite in the anode absorbs.
The problem with using larger amounts of silicon is because as it absorbs the lithium, it can expand around 300 per cent during the charge and discharge cycles.
This means both the battery and the device the battery goes into need to be able to handle the expansion — something researchers haven’t been able to achieve.
But Lithium Australia thinks it may be onto something.
“There are plenty of people researching it and there are plenty of batteries that have got a bit [of silicon] in the anode,” managing director Adrian Griffin told Stockhead.
“The issue here is how far can we push that; how much can we get in there and what do you need to get a lot of it in there without destroying the anode itself as it cycles through charge and discharge?
“We certainly believe we’ve found something that is capable of getting quite a bit of silicon metal in there.”
Lithium Australia revealed earlier this week that it was partnering with a battery researcher and planned to build facilities for the development of graphite/silicon anodes.
Mr Griffin says the increase in silicon would not mean completely replacing graphite.
“It’s not a direct substitution,” he explained.
“We are trying to make the graphite framework very porous and putting silica particles in the porous parts of that medium.”
American car giant Tesla uses roughly 7 per cent silicon in the anode of its batteries.
Mr Griffin said Lithium Australia is looking at increasing the amount of silicon “well and truly” beyond that.
No more graphite?
While Lithium Australia’s plan is to still use graphite in the anode, one US-based company says it can completely replace graphite with silicon.
California-based Sila Nanotechnologies wants to have its technology in more than 1 million electric vehicle batteries by 2023, chief Gene Berdichevsky told Reuters recently.
According to Sila, its materials can lower the cost of a battery on a dollars-per-kilowatt-hour basis.
But Mr Griffin said the key benefit of using more silicon had less to do with reducing cost and more about higher energy density and better battery performance. Although it also doesn’t increase the cost.
Lithium Australia decided to look at improving the anode in lithium-ion batteries because the opportunities to improve the cathode have pretty well been exhausted.
“My belief is, certainly with conventional cathodes, the chemistries are very efficient,” Mr Griffin said.
“There’s not a lot of room for increasing the battery performance by fine tuning the basic chemistries of the cathodes.”
Lithium-ion will be the major battery technology for the next few years.
At the moment it’s more about refining the chemical make-up of a lithium-ion battery rather than moving to another type of battery.
“The immediate progress you are likely to see in battery technology is towards advanced lithium-ion technologies which are maximising the performance of existing chemistries,” Benchmark Mineral Intelligence senior analyst Andrew Miller told Stockhead previously.
Electric car makers are focusing on two chemistries: nickel-cobalt-aluminium (NCA) and nickel-cobalt-manganese (NCM or NMC).
American car giant Tesla prefers NCA, while the NCM chemistry is more popular among its rivals.