- Harvard researchers have created a battery that is inspired by the BLT sandwich
- They say a lithium-metal battery can be charged and discharged 10,000 times
- Startup in Massachusetts granted license to manufacture batteries on a large scale
A ‘game-changing’ new battery for electric vehicles (EVs) that charges in three minutes and lasts for 20 years may soon be coming to new cars.
Aidan Energy, a start-up based in Waltham, Massachusetts, has been granted a license and $5.15 million in funding to produce large-scale battery designs to fit EVs.
The battery developed by Harvard scientists is lithium metal, not the lithium ions found in EVs already on the market.
Its complex design, inspired by the BLT sandwich, prevents the development of troublesome ‘dendrites’ that grow in lithium-metal batteries and shorten their lifespan.
Harvard has granted Aden Energy an exclusive license to develop solid-state, lithium-metal batteries. The startup aims to scale up the battery to a palm-sized ‘pouch cell’ – which consists of components encased in an aluminum-coated film (pictured).
Long-lasting, quick-charging batteries are essential to the expansion of the EV market, but today’s lithium-ion batteries fall short, as they are too heavy and expensive and take too long to charge (File Photo)
Currently, EVs have lithium-ion batteries that wear out over time and last seven or eight years, depending on how much they are used – much like smartphone batteries. .
Lithium-ion vs. Lithium Metal
Lithium metal batteries contain the metal lithium, while lithium-ion batteries contain lithium that exists only in the ionic form in the electrolyte.
Most lithium metal batteries are not rechargeable whereas lithium ion batteries are. However, there are rechargeable lithium-metal batteries in development.
Lithium-ion is currently powering EVs already in the market for laptops and smartphones, along with Tesla and other companies.
Long-lasting, quick-charging batteries are essential to the expansion of the EV market, but today’s lithium-ion batteries fall short, as they are too heavy and expensive and take too long to charge.
Source: IATA/Green Battery
These lithium-ion batteries can be replaced, but they can cost thousands of pounds, which means drivers are often better off buying a new EV.
But this new solid-state, lithium-metal battery could extend the lifespan of an EV to a length comparable to that of petrol and diesel cars – up to 20 years – without ever needing to replace the battery in the meantime.
In the lab, the team’s battery prototype has achieved battery charge rates as fast as three minutes, with more than 10,000 cycles over its lifetime.
The new technology is created by Xin Li and colleagues from the Harvard John A. Paulson School of Engineering and Applied Science (SEAS).
Aidan Energy was founded in 2021 by Lee along with William Fitzhugh and Luhan Ye, both of whom contributed to the development of the technology as graduate students at Lee’s Harvard lab.
The startup aims to scale the battery down to a palm-sized ‘pouch cell’ – which consists of components encased in an aluminum-coated film – and then towards a full-scale vehicle battery in the next three to five years.
“We have achieved 5,000 to 10,000 charge cycles over the lifetime of a battery in the laboratory, compared to 2,000 to 3,000 charging cycles for the best ever, and we see no fundamental limit to increasing our battery technology,” said Took. ‘It could be a game changer.’
Lithium-metal batteries hold the same amount of more energy than traditional lithium-ion batteries and charge in a fraction of the time.
But they are prone to the formation of ‘dendrites’ – small, hard tree-like structures that accelerate battery failure.
So researchers have attempted to harness the potential of solid-state, lithium-metal batteries using a unique BLT-inspired design.
Think of the battery as a BLT sandwich. First comes the bread (lithium metal anode) and then comes the lettuce (the graphite coating). Next, a layer of tomatoes (the first electrolyte) and a layer of bacon (the second electrolyte). Finish it off with another layer of tomato and the last piece of bread (the cathode).
What are Dendrites?
Dendrites are small, hard tree-like structures that can develop inside a lithium battery.
Their needle-like projections are called whiskers.
They increase unwanted reactions between the electrolyte and the lithium, accelerating battery failure.
Dendrites and whiskers are preventing widespread use of lithium metal batteries, which have higher energy densities than commonly used lithium-ion counterparts.
Source: DOE/Pacific Northwest National Laboratory
Lithium-metal batteries use lithium in its pure metal form, rather than the lithium compounds used in lithium-ion batteries.
Meanwhile, ‘solid-state’ refers to the use of solid electrodes and a solid electrolyte instead of the liquid or polymer gel electrolytes found in lithium-ion.
‘If you want to electrify vehicles, a solid-state battery is the way to go,’ said Lee, Aden Energy’s scientific advisor.
‘We set out to commercialize this technology as we see our technology as unique compared to other solid-state batteries.’
Batteries have three main components – anode, cathode and electrolyte.
The electrolyte (usually a chemical) separates the anode and cathode and speeds the flow of electric charge between the two.
Lithium-ion batteries carry lithium ions from the cathode to the anode during charging.
But when the anode is made of lithium metal, needle-like structures called dendrites form on the surface.
These structures grow like roots in the electrolyte and pierce the barrier separating the anode and cathode, which can cause a battery fire.
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