Nobuyuki Imanishi, Ph.D. at Mie University in Japan reports progress on a “breathing” battery that has the potential to one day replace the lithium-ion technology of today’s electric vehicles.

The main difference between lithium-ion and lithium-air batteries is that the latter replaces the traditional cathode, a key battery component involved in the flow of electric current, with air. That makes the rechargeable metal-air battery lighter with the potential to pack in more energy than its commercial counterpart.

Lithium ion Compared to Lithium Air.  A  lithium-air battery uses oxygen in the air for the cathode and lithium metal for the anode allowing for a smaller and lighter package.

Lithium ion Compared to Lithium Air. A lithium-air battery uses oxygen in the air for the cathode and lithium metal for the anode allowing for a smaller and lighter package.

At issue is sales of electric vehicles (EVs) nearly doubled in 2013, but most won’t take you farther than 100 miles on one charge.

Imanishi points out, “Lithium-air batteries are lightweight and deliver a large amount of electric energy. Many people expect them to one day be used in electric vehicles.” Imanishi’s team presented their work at the 247th National Meeting & Exposition of the American Chemical Society (ACS) in Dallas last week.

Lithium-air batteries are a high potential and an exciting technology to watch  But, they still have some kinks that need to be worked out. Researchers are forging ahead on multiple fronts to get the batteries in top form before the batteries can enter the mass market.

One of the main components researchers are working on is the batteries’ electrolytes, the materials that conduct electricity between the electrodes. There are currently four electrolyte designs, one of which involves water. The advantage of this “aqueous” design over the others is that it protects the lithium from interacting with gases in the atmosphere and enables fast reactions at the air electrode. The downside is that water in direct contact with lithium can damage it.

Imanishi’s noted that adding a protective material to the lithium metal is one approach, but this approach typically decreases the battery power.  To solve the power decease the team developed a layered approach, sandwiching a polymer electrolyte with high conductivity and a solid electrolyte in between the lithium electrode and the watery solution. The result was a unit with the potential to pack almost twice the energy storage capacity, as measured in Watt hours per kilogram (Wh/kg), as a lithium-ion battery.

Imanishi said, “Our system’s practical energy density is more than 300 Wh/kg. That’s in contrast to the energy density of a commercial lithium-ion battery, which is far lower, only around 150 Wh/kg.”

The laboratory battery shows a lot of promise, with high conductivity of lithium ions, and the ability to discharge and recharge 100 times.  In addition to powering EVs, lithium-air batteries could one day have applications in the home, thanks to their low cost. Power output remains a big hurdle, but Imanishi said his group is committed to honing this approach, as well as exploring other options, until lithium-air becomes a commercial reality.

Imanishi’s work was supported by the Japan Science and Technology Agency.

Now what jumps out of the news is a innovation that seems, well, shocking.  Who would have thought to use two electrolytes to solve the problem?  Seems great now, but leads to another question – what other technological hurdles are in need of some strikingly easy, but difficult to imagine concepts?

Congratulations are definably in order for the Mei University team.


1 Comment so far

  1. mmarq on April 7, 2014 4:27 PM

    Instead of waiting for the kinks to be worked out… for only the ‘double’ of the miserably obsolete Li-ion of today

    This one has more than double (experimental tested) of the todqay obsolete Li-ion 292mAhg⁻1 between 1.5 and 4.5 V gives essentially 700Wh/kg (Tesla model S is 265Wh/kg)…

    … or since this is more like a capacitor ( no fade, no memory, huge power) its like 83.3mAhg⁻1 capacity for a current density of ~2.5Ag⁻1 and 10KW/kg of power ( the point of the ‘inventor’), meaning 100Kg of active material (even HEV have more) in a battery with this would have 1MW or 1340 hp (horse power)…

    who the heck! needs an ICE ? … hamsters on a treadmill ??… any other day comes out a new “promising chemistry” but that yet needs kinks to be worked out … when in my example, no need binders, no need additives or solvents or doping or coating techs or anything expensive or complicated, all the kinks are more than worked out, so simple by that “nature” article you could build one yourself, and the “revolution” be on the streets… yesterday ! (article is 1 year old).

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