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Researchers at Japan’s AIST Propose a Rechargeable Ni-Li Battery with Hybrid Electrolyte; Ultrahigh Theoretical Energy Density Plus High Power Potential

Key components, cell voltage, and cell capacity of Li-ion battery (a), Ni-MH battery (b), and the proposed Ni-Li battery (c). Credit: ACS, Li et al. Click to enlarge.

Researchers at Japan’s National Institute of Advanced Industrial Science and Technology (AIST) have developed a prototype of a battery that can simultaneously offer the high cell voltage of Li-ion cells and the large cell capacity of Ni-MH cells: a rechargeable nickel (cathode) / lithium metal (anode) battery using a hybrid aqueous and organic electrolyte separated by a superionic conductor glass ceramic film.

The proposed Ni-Li battery offers both a high cell voltage (3.49 V) and a large cell capacity (268 mAh/kg), which together create an ultrahigh energy density. The theoretical energy density calculated using only the active electrodes and cell voltage for the Ni-Li battery is 935 Wh/kg. With the same calculations, NiMh offers 214 Wh/kg, and cobalt oxide Li-ion cells offer 414 Wh/kg. A paper on the proposed Ni-Li system was published 5 October in the Journal of the American Chemical Society.

“The amount of electrical energy E (Wh/kg) that a battery is able to deliver is a function of the cell voltage U (V) and capacity Q (Ah/kg), both of which are linked directly to the chemistry of the system.”
—Li et al.

Current prominent battery systems such as Li-ion and NiMH demonstrate “huge gaps” between expected and practical performances, the researchers note. Li-ion cells are hobbled by the limited inherent capacity of their cathode materials; by their low power densities which are restricted by the slow electrode kinetics relating to Li intercalation/deintercalation from the host materials; and safety issues.

As for NiMH, although both the cathode and anode material can deliver a large capacity, the cell voltage is only 1.32 V due to the limitation of aqueous electrolyte.

One radical exploration is to break the routine of classical batteries which involves a single electrolyte. If an aqueous electrolyte and organic electrolyte can be smartly integrated in one battery, it would enable state-of-the-art combination choices for the existing battery chemistry. Recently, a superionic conductor glass ceramic film (LISICON) with stability in aqueous solution and its application in a Li-air battery has been reported. [Earlier post.]

Here, we proposed integrating a nickel hydroxide electrode working in an aqueous solution as the cathode and a Li metal working in an organic electrolyte as the anode by a LISICON film to fabricate a rechargeable Ni-Li battery.

Li is the most negative metal while at the same time possessing an ultrahigh capacity of 3, 860 mAh/g, thus facilitating the design for high energy density. However, the uneven plating of Li in the form of dendrites during discharge-recharge cycles may puncture the polyolefin thin separator, leading to short circuit hazards. In the Ni-Li battery, the rigid ceramic LISICON film is hardly punctured by Li dendrites thus enabling the utilization of Li metal.

As for a cathode electrode, nickel hydroxide, with a less positive potential and an aqueous solution as the electrolyte, is inherently safer than the case of the cathode in the Li-ion battery.

—Li et al.

Work on the Ni-Li battery is in very early stages, the researchers said. Although the power ability of the Ni-Li battery is expected to be superior to that of the Li-ion battery regarding the electrode kinetics, the current data “are not satisfying” due to the low conductivity of the LISICON film.

Although assembly of such a battery seems “somewhat complicated”, they wrote, the implementation of a hybrid electrolyte can provide a variety of choices for electrode materials.

In summary, we propose a rechargeable battery system by integrating two reversible electrode processes associated with an aqueous and a nonaqueous electrolyte, respectively. The prototype Ni-Li battery promised an ultrahigh theoretical energy density as well as a high power potential, which reinforced the view that it is an important avenue to fulfill the best-performing combination for an electrode/electrolyte/electrode system.

—Li et al.


  • Huiqiao Li, Yonggang Wang, Haitao Na, Haimei Liu and Haoshen Zhou (2009) Rechargeable Ni-Li Battery Integrated Aqueous/Nonaqueous System. J. Am. Chem. Soc., Article ASAP doi: 10.1021/ja906529g



Although assembly of such a battery seems “somewhat complicated” Good luck..


I've got to give them props for a novel approach.


Regulators won't like the use of lithium metal rather than ions, and the dendrite problem has also been holding back lithium-sulphur chemistry. If they can find a nano-way to deal with this then we're on for 500+ Wh/kg.


Somebody will come out with a 500+ Wh/Kg batteries by 2020. That's when affordable-practical extended range BEVs will surface and be mass produced.

Meanwhile, basic PHEV-10, with smaller (upgradable) battery pack and a selectable small genset could be one of the best option (till 2020) or so.

People with deeper pocketbook could always start with otional larger battery pack and genset. Buyers should have the option.

Mini, very light weight, e-city cars are possible now.


Amen, HarveyD.
What is taking so long to build a small (light weight), low-cost EV. Even with limited range it could be very popular.


"The proposed Ni-Li battery offers both a high cell voltage (3.49 V) and a large cell capacity (268 mAh/kg)"
The second figure should be 268 mAh per *gram*. That's how you arrive at 935 Wh/kg energy density.



Agree with you. All changes that time. The Toyota Prius took almost 10 years to pick up speed. BEVs will probably follow the same slow introduction pace, unless......


The introduction of EVs can happen much faster if we really run out of oil as the peak-oil people say. If that happens and oil prices skyrocket than the complete migration to EVs could happen only in 5-10 years.


It's possible that even now, major alternate fuel investments/major auto firm EV commitments are holding oil prices lower.

In the past, alternative power investment collapsed a few business quarters after oil prices were reduced.

Just the EXISTENCE, even less convenient, of a oil vehicle alternative is powerful.


The belief that I find amazing is "they will come up with something" and "if they build a whole lot of them, the price will come way down". There seems to be an abundance of faith in the technologists, so why not jump in the Hummer and take a long drive?


IBM and a few others are apparently working on a lithum-Air battery pack with 10x the energy capacity for 500+ miles BEVs.

If they succeed, practical highway BEVs may be around by 2015/2020.

The AIST guys also have a development in Li-Air battery:

It looks that this Ni-Li approach is an alternate in cathode: the O2 + 2H2O + 4e- → 4OH- in Li-Air becomes Ni(OH)2 + 2e- → Ni + 2OH- in Ni-Li and thus no O2 is needed.


Nice insight, Victor

Henry Gibson

The combined battery technology of CISRO, Firefly and EFFPOWER just using lead can make a very good cheap car when used with a small range extender. All that is needed is mass production.

A high energy density, but low power density Nickel-Chloride-Sodium battery can be built. It could approach 300 watt-hours per kg. It could be used combined with EFFPOWER batteries or NiMH or Flywheels for power. Ultracaps can be considered. ..HG..


Kelly, correct marketplace competition will bring the lowest price.
Monopolies encourage the opposite.The oil industry is a centralised, officially supervised cartel the shareholders are entitled by law to maximum profit.
Without choice people have no option.

Henry Gibson

Considering the weight of the rest of the battery system, the use of lightweight lithium is not very important. It is of no importance for stationary batteries. The weight of the lithium becomes even less important when the vehicle and passenger weight is considered.

About the lightest weight electric source for automobiles would be isotope 94-238. It is quite safe when protected by a few fractions of an inch of steel. It can be used to run a free piston stirling generator from Infinia or elsewhere. Infinia has made a 3kw unit and this is far more than enough for much travel but can be replicated. The price is very-very-very much too high. You would need 18 kilograms for a 3 kW Stirling generator and even still it would be producing only 1.5 kW at the end of 88 years. This is more than the US has. ..HG..


I just looked at the aist website that Victor posted. It looks like the lithium-air cell they are developing is RECHARGEABLE.

This concept it therefore unlike most metal-air proposals that would require changing of bulky slurries or cassettes at a garage.

I really want to see how efficient and quick the charge / discharge cycle of their rechargeable lithium-air cell is.

If it can be made to recharge quickly with decent cycle life then they've basically cracked the 2,000 Wh/kg automotive EV battery. IMO that would be the biggest story yet on GCC.

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People with deeper pocketbook could always start with otional larger battery pack and genset. Buyers should have the option.
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