London â€” Aluminum batteries will likely be on a par commercially with lithium-ion batteries within the next 10-15 years, if not indeed supplanting them in all but a few strictly necessary applications, researcher Niklas Lindahl from the Department of Physics at Chalmers University of Technology told S&P Global Platts in an interview.
Once manufacturing has been established on an industrial scale, aluminum-ion batteries (AIBs) — currently in an R&D phase — would likely represent a better and cheaper charge carrier than lithium-ion batteries (LIBs) whilst also being less environmentally harmful, Lindahl added.
A group of researchers from Swedish Chalmers University of Technology and the National Institute of Chemistry in Ljubljana, Slovenia, is working to resolve certain issues withholding commercial use of AIBs.
The team has recently made a leap forward with its new battery concept that has twice the energy density of best available AIBs, according to a statement on the university’s website.
From a sustainability point of view, LIBs use scarce graphite, lithium and cobalt resources. Also, due to high temperatures during synthesis, LIB-cathode production — in China or Poland — yield high levels of emissions. In contrast, AIBs rely on abundant materials and lower temperature organic synthesis, Lindahl said.
“There is no such production yet [of AIBs] and it is difficult to say which materials will eventually be used in the battery cells. But our assumption is based on lower prices for input materials. That goes for aluminum versus lithium,” Lindahl said.
On the London Metal Exchange, a kilogram of aluminum now trades for $1.80/kg versus $9.20/kg and $11.20/kg for lithium carbonate and lithium hydroxide, respectively.
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It is cathode material — typically containing lithium and cobalt and often also nickel and manganese — that drives up the cost of LIBs, whereas graphite-made anode comprises a much smaller part, Lindahl said.
In AIBs, previous designs have used graphite as the cathode — with the anode built of aluminum — but graphite does not provide enough energy to create performant battery cells. The developers behind the new AIB concept have overcome the drawback by replacing graphite with an organic, nanostructured cathode made of the carbon-based molecule anthraquinone; their solution boosted energy density.
However, several more challenges need addressing before aluminum batteries become more commonly used, key among which are the technology’s imperfect electrolyte and charging mechanisms.
The Gothenburg-Ljubljana team also aims to get rid of chlorine in the electrolyte as currently it is highly corrosive. Another issue the researchers are concerned with is voltage for AIBs being lower than for LIBs.
“It means more cells need to be connected in series, which could be a limitation for applications where high voltage systems are the standard,” said Lindahl, adding that high-performance electric vehicles are unlikely to be converted to AIBs.
“The theoretical energy density of our novel concept is half as much as what is obtained in commercial LIBs, but if compared to LIB’s theoretical energy density, which is a more fair comparison, our concept reaches circa one fourth of LIBs. Still, the cost/kWh could be lower for our concept,” Lindahl said.
AIBs will go first to applications where cost/kWh and sustainability is more important than energy density, for example stationary storage of solar and wind power.
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