New lithium-air battery design shows promise - lithium air battery
New design for lithium
Air batteries overcome several major obstacles to the concept. Lithium-
Air batteries can be more dense than today's lithium storage
Ion batteries make them promising in electric vehicles.
The design, published in the journal Science, uses a sponge graphene electrode and a new chemical reaction to drive the battery.
It loses a lot less energy and can be charged more times than previously tried lithiumair batteries.
Hope for lithium-
Air batteries are chemical reactions that they will burn in conventional air to release electricity: lithium ions move from positive to negative, where they are oxidized.
Currently, engineers at the University of Cambridge supporting this new effort have only manufactured laboratory test devices operating in pure oxygen rather than air.
In the first case, however, the prototype can run when oxygen is wet.
What we really want is a real lithium. air battery -
Professor Claire Gray, senior author of the study, told BBC News that "it only absorbs air without having to remove carbon dioxide, nitrogen and water . ".
"Now we have a system that can withstand at least a lot of water.
"Although Professor Gray's team has made significant progress, they say that a commercial lithium --
The air battery is at least 10 years away.
Their demonstration units, for example, are still quite slow.
"When you want the battery to happen in minutes and seconds, our battery takes a few days to charge and discharge," explains Professor Gray . ".
But this design has great advantages.
It packs energy at a density that is almost the limit of lithium theory. air batteries.
This energy density will eventually push electric vehicles to countries, not cities, in a single charge.
It also charges at a voltage of 3.
Discharge at 0 and 2. 8 volts -
Efficiency of 93%
This means that it loses very little energy as a heat.
This is close to the current efficiency of lithium.
Ion battery, compared with the previous lithium battery has been greatly improvedair efforts.
It is essential that these test batteries can be charged and charged more than 2,000 times, with little effect on their functionality.
"For months, we have been able to circulate our cells with little evidence of side effects," Professor Gray said . ".
Part of the reason for this success is the design of the cathode, which is made of a sponge
Like the arrangement of grapheneThis so-
The so-called "miracle material" is from one-atom-
Thick carbon sheet.
When the battery is discharged, the holes on the porous cathode allow the reaction product to accumulate and then dissolve again while charging.
The chemical reaction itself is also crucial.
Professor Gray's team used an additive, lithium iodine, to change the chemical composition of the core of the battery.
Instead of lithium peroxide (Li2O2) like most other lithium)
Air design, the discharge reaction produces lithium hydroxide (LiOH) at the cathode ).
When the battery is charged and the lithium ion returns to the anode, the hydroxide can be completely dissolved again.
"It's a very different chemical reaction;
"It gives us a new way of thinking," said Professor Gray.
"It's a commercial way, but it does provide some interesting new research directions.
Dr. Paul Shearing, a chemistry engineer at University College London, said Cambridge design is an "important step" towards lithium"
Air batteries in the lab
"This is an impressive job," he told the BBC . ".
"[The lithium air battery] has been plagued by problems, especially with poor cycle life.
It is possible to solve these problems.
"If successful, Dr. Shearing added that lithium-
Air cells can bring about huge changes as their energy density almost matches the energyper-
Kilograms packed with gasoline.
As Professor Gray said: "The car battery from London to Edinburgh will be energy density.