New rechargeable cell has 7 times higher energy density than lithium-ion cells

By Motohiko Hamada

A Japanese research group developed a rechargeable battery based on a new principle in cooperation with Nippon Shokubai Co Ltd.

The group is led by Noritaka Mizuno, professor at the School of Engineering, the University of Tokyo. The new battery uses the oxidation-reduction reaction between oxide ions and peroxide ions at the positive electrode. The group proved that peroxides are generated and dispersed due to charge and discharge reactions by using a material made by adding cobalt (Co) to the crystal structure of lithium oxide (Li2O) for the positive electrode, verifying a battery system based on a new principle.

The new technology can realize an energy density seven times higher than that of existing lithium-ion rechargeable batteries, increase capacity, lower price and enhance safety. It is expected to be used for batteries for electric vehicles (EVs) and next-generation stationary batteries.

The oxidation-reduction reaction between Li2O and Li2O2 (lithium peroxide) and oxidation-reduction reaction of metal Li are used at the positive and negative electrodes, respectively, of the new battery. The battery has a theoretical capacity of 897mAh per 1g of the positive/negative electrode active material, voltage of 2.87V and theoretical energy density of 2,570Wh/kg.

At that time, the energy density is 370Wh per 1 kg of the positive/negative electrode active material, which is about seven times higher than that of existing Li-ion rechargeable batteries using LiCoO2 positive electrodes and graphite negative electrodes. The theoretical energy density of the new battery is lower than that of lithium-air batteries (3,460Wh/kg). But it has a sealed structure like conventional lithium-ion batteries, realizing a high reliability and safety.

This time, as the positive electrode material, the research group used a material made by using a planetary ball mill to add Co to the crystal structure of LiO2. And the group proved that it is possible to realize a battery system in which the oxidation-reduction reaction between oxides and peroxides reversibly proceeds. And it proved that (1) peroxides are generated in the positive electrode for charge, (2) the peroxides are dispersed for discharge and (3) those reactions are repeated, by quantitatively analyzing the peroxides.

The group also proved that neither O2 nor CO2 is generated in the range where it is possible to reversibly charge/discharge the battery.

The positive electrode used in the demonstration test enables to repeatedly charge/discharge the battery with a capacity of 200mAh/g and to quickly charge/discharge the battery with a large current. The positive electrode has a smaller mass ratio of Co than LiCoO2, which is used for existing lithium-ion batteries, and possibly lowers costs.

© Japan Today

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If these work, once they get these into production, it will be great for solar power. The main problem now is we can't store the electricity in batteries because they're too expensive for the home owner.

10 ( +11 / -1 )

....And they need to last many, many cycles! Exciting news!

3 ( +5 / -2 )

This is exciting news. Even if production proves to be similar/more expensive than existing batteries, the increase in capacity/weight will have profound effects on everything portable that we use (thinner/lighter phones for one!)

3 ( +4 / -1 )

They don't really state how fast the charge would be, but just say 'quickly'. If they can manage to find a way to charge a large battery within a few minutes, I think that it would give electric cars a BIG boost. I'm also wondering what the life cycle of this type of battery would be and it has a reduced capacity like the current batteries when it gets older.

3 ( +4 / -1 )

They already have 20 minute quick charges for electric cars. I believe it gets them to 80% charge

0 ( +0 / -0 )

Any chance of seeing these in mobile electronics? It seems the advancements in battery technology have been stagnant, sans a few very minor improvements. With all the other oh-so exciting news in technology it feels though as if battery cell development had hit a brick wall in what's technically possible.

1 ( +1 / -0 )

They already have 20 minute quick charges for electric cars. I believe it gets them to 80% charge

True Afano, but it also wears down the longevity of the electrical system doing this. I imagine it's only for emergency purposes.

3 ( +3 / -0 )

And there are prople saying Japanese technology is irrelevant.

3 ( +4 / -1 )

These will be useful in the next few years when we all live on Mars

0 ( +0 / -0 )

great! i hope this goes well.

battery technology has been desperately needing some decent advancement for a looong time.

3 ( +3 / -0 )

I've read about 50 new battery technology stories in the past 3 years and not one has actually made it to market. I'm sure one will at some point but I'm not getting my hopes up too high yet. That said, I can dream of a Car that could go 1000 miles on a single charge.... or a cell phone I only have to charge once a week. If a battery could hold 20 times current lithium batteries.... the world would change and a lot of current businesses would die out.

0 ( +0 / -0 )

a Car that could go 1000 miles on a single charge even 500miles would be enough considering most people would drive that much in a day even during vacations.

2 ( +2 / -0 )

In the last half of the 1900s, the greatest advances were in computer power. But even then, there were always limitations - memory/storage, display, and portability.

We now have stratospheric amounts of memory and storage, due to dramatically higher magnetic densities on disks and the emergence of solid state drives. (Remember when the Sony Mavica camera looked like such a great idea because it could store photos on a floppy disk?)

It used to be that you had to have a CRT to work with a computer. The ubiquity of LCD (and now OLED) displays means we can see anything, anywhere. Look at the tiny Apple iPod Nano, the entire front of which is a display.

Portability is the last of the three major steps. It used to be that you had regular batteries, then it was NiCd rechargeables, now we have NiMH and LI batteries that hold huge amounts of power(relatively speaking) and don't weigh a lot.

Imagine what we'll have ten years from now, when today's technology will look quaint. It's an exciting time to be alive.

1 ( +2 / -1 )

Japan technology is always fascinating.

0 ( +1 / -1 )

Sounds like it has great potential.

1 ( +1 / -0 )

If they can get this battery design into actual production, a place where it would hugely everyone is cellphones. It could mean cellphones with three to four times the battery life per charge compared to today's lithium-ion batteries.

0 ( +0 / -0 )

How to tell if things are for real: A little leakage but mostly wrapped up in secrecy, yes, and buy; a lot of fanfare even before maturity, too much news leaks, no: probably aiming at government subsidies as well as stock market manipulations.

0 ( +0 / -0 )

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