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Univ. of Tokyo researchers demonstrate new “oxygen-rocking” battery

Researchers at the University of Tokyo have developed a battery based on the concept of a combination of a perovskite-type cathode and a low-electrode-potential anode that can achieve high energy densities through the use of organic rather than aqueous electrolytes. The work is derivative of their earlier investigation into a “oxygen-rocking batteries” reported in 2012. (Earlier post.)

Batteries based on this system allow the use of various anode materials, such as lithium and sodium, without the requirement to develop new cathode intercalation materials. In the new study reported in the Journal of the American Chemical Society, they used the concept and demonstrated a new battery based on a CaFeO3 cathode with a sodium anode, in conjunction with a NaClO4/triglyme electrolyte.

We have recently both proposed and demonstrated an oxygen rocking battery in which oxygen atoms are shuttled between a cathode and an anode composed of iron-based perovskite oxides Ca0.5La0.5FeOz, with 2.58 ≤ z ≤ 2.63 for the anode and 2.75 ≤ z ≤ 2.863 for the cathode. These materials have been found to allow topotactic [transformation within a crystal lattice] and reversible extraction/insertion of oxygen atoms.

…During discharge, the CaFeO3 cathode undergoes topotactic extraction of oxygen atoms and changes to CaFeO2.5, and the extracted oxygen atoms react with sodium ions to form sodium oxides. This cathode has a theoretical specific capacity of 187 mAh g-1 if the final discharge product is NaO2.

—Hibino et al.

The team developed a process that allows the oxidation of CaFeO2.5 under milder conditions than usual. They mixed CaCO3 (>99.99%, 4.00 g) and α-Fe2O3 (99.9%, 3.19 g) were mixed together and ground in an agate mortar for 5 h, following which the mixture was heated to 1000 °C at 20 °C min−1, held at 1000 °C for 5 h, and then cooled to room temperature in air.

The resulting powder was ground again with an agate mortar and pressed into a thin disk, which was subsequently heated to 1100 °C at 20 °C min−1, held at 1100 °C for 24 h, and cooled to room temperature in air to obtain CaFeO2.5.

For electrochemical measurements they used a three-electrode beaker cell employing metallic sodium as the counter and reference electrodes and a 1 M NaClO4/triglyme electrolyte solution.

They also reported that it was also possible to prepare an iron-based perovskite-type material SrFeO3 according to the same method as used to synthesize CaFeO3, and these materials could be reversibly reduced and reoxidized in an organic electrolyte using not only a sodium anode but also lithium and magnesium anodes.

This research was supported by the Japan Society for the Promotion of Science (JSPS) through its “Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program)”. A part of this work was supported by “Nanotechnology Platform” (Project 12024046) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.


  • Mitsuhiro Hibino, Ryuji Harimoto, Yoshiyuki Ogasawara, Ryota Kido, Akira Sugahara, Tetsuichi Kudo, Eita Tochigi, Naoya Shibata, Yuichi Ikuhara, and Noritaka Mizuno (2013) “A New Rechargeable Sodium Battery Utilizing Reversible Topotactic Oxygen Extraction/Insertion of CaFeOz (2.5 ≤ z ≤ 3) in an Organic Electrolyte.” Journal of the American Chemical Society doi: 10.1021/ja411365z



Thank you Santa!
I wanted a higher energy density battery in my stocking!

And a Merry Christmas to all here!
Or at least, most! ;-)


Not for this year Dave.

You may ask for a 5-5-5 battery-in-a-bag for Xmas 2020 or so or a shiny Tesla ultra light weight extended range BEV for Xmas 2022 or so.

A Merry Xmas and Happy New Year to you too.


I hope for those hooligans a.k.a Greenpeace crew are out of of the evil empire by new year,and Pussy riot get to rock on at the Kremlin, which is even closer to god.
(nice to see them going up in the world.)

Who would have thought Mr Putt'n would be playing universal Santa.- very Xmasy

Shows anything IS possible, all you need is love.


Why should everything be about energy density?  Cheap, efficient and long-lived will do for a pile of things, bulky and heavy or not.  Making the whole battery out of dirt-cheap minerals like sodium, calcium and iron means no resource barriers to massive deployment.

Roger Pham

Agree with you, E-P. The Panasonic NCA 18650 as used by Tesla with 250 Wh/kg and $170/kWh is very adequate for a very good PHEV-50 that can compete with a comparable ICEV in term of purchasing cost and internal space. With 50-mile AER, this PHEV-50 can cut petroleum by as much as 80%, yet will solve the range, cost, weight, battery aging, and lack of quick charging issues of BEV's.


Merry chrismas to all scientific green aficionado and i wish you high energy density, long range and fast refill.

Bob Wallace

Where do you get the $170/kWh? Solid evidence? I'm trying to put together whatever facts may be found.

On a GM Parts Store site a replacement battery for the 2012 Chevy Volt is listed at $2,305.88. No core (used battery) return required.

That's 16 kWh. $144.12/kWh. Retail.

Another GM parts store is selling for $2,620. $164/kWh.

These prices seem so low that they seem wrong.

At $120/kWh (wholesale) a 200 mile range EV battery 65 kWh pack in a Tesla-sized car 65 would cost under $8k. That's not much more than the cost of an ICE and all its systems.


Fantastic research Bob.
That price is unbelievable.
Its game over for regular ICE at that price!


And a late Merry Christmas to everyone!

gorr...great wishes! :-)

BobW, great info and things are looking more and more encouraging.

DaveM....sorry I left and took the good weather with me...hopfully you guys didn't get too cold for Christmas! :-)


You did rather leave flooding behind, but I won't be too harsh on you as it appears that many regions of the US have had a dusting of snow! ;-)

Gorr, thanks for the wishes, and I certainly intend to get a fast refill in a moment!


Here's one for the number crunchers engineer artists and dynamic physics imaginates and inspirates.

I am currently working on a dirt cheap mineral storage for a free energy generator.

I have to refine the cinematics a bit but basically involves braking either the universe or the planet
(whichever is easier as I'm basically lazy)

The magnetron has super conducting oxygen free shunts traversing the ionosphere. The terminal end is inserted into a sodium salt soution on the anode with the cathode - well the rest is obviously comercial in confidence.

The only question yet unresolved is

"How can this be made wearable without sacrificing the essential elements"

I have done the math and it should work, but still require affordable, independent verification prior to listing.



uhhhhh....huh? Are you serious? LOL


The locals would use the term 'deadly'.au

Bob Wallace

Just don't take those prices as gospel at this point in time.

I'm trying to get some confirmation.

I found a comment on a Volt web site that someone had checked the price through his buddy's repair shop and their price was $1,900 for a 2012 Volt battery. Supposedly what the shop would pay. And that would make GM's cost much lower.

If you can think of any way to confirm/shoot down those prices pitch in. If it's true, it's wonderful.

But it sounds too good to be true. I'm treating it as a lead, in no way a fact.


apologies wrong confusing link


I'm getting a whiff of eau de bovine from Arnold.


Foxed,the methane levels are too high,also the flux doesn't cut at 90 degrees so the power levels arre right down.
The front Panel won't support more illumination than the solar system and the cinematics demand that to be free spinning.This is not such a problem as the axle is relatively slow spinning - about 900 miles an hour according to A Monty, P Thon et all so braking this is not a problem.
We plan to make a start in the new year, as there are still buttons to sew on.Tricolor organic LeD can be sourced locally. The good news is Ladyb Ada can supply the conductive polymer nano threads.
A demonstration version is scheduled for the northern hemisphere spring season.
We will keep you informed as important milestones are reched - or maybe not.


I'm sure you WILL retch important milestones!

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