Published on October 30th, 2013 | by Nicholas Brown


A123 Partners With SolidEnergy To Achieve 4X Energy Density In Lithium-Ion Batteries

October 30th, 2013 by  

A123 Venture Technologies has teamed up with SolidEnergy to develop lithium-ion batteries with four times the energy density of conventional lithium-ion batteries. The technology is called a Solid Polymer Ionic Liquid (SPIL) electrolyte.

A123’s standard 18650 batteries only achieve 95 Wh/kg, which is still much better than lead-acid and NiMH batteries, but energy density was the weakness of A123 battery technology.

Conventional lithium-ion batteries are currently in the low 100 Wh/kg range. About 110. Multiply that by four, and you have a whopping 440 Wh/kg. This technology would reduce the weight of the Nissan Leaf’s battery from 660 pounds (due to its below-average energy density of 80 Wh/kg) to a measly 54 pounds. That is so lightweight, you could lift it with one of your bare hands! (Well, if you are fairly strong.) That would make the Leaf light enough that it could travel much further on a charge, or would allow for more batteries to be put in the Leaf, also allowing for much longer range.


Mujeeb Ijaz, President of A123 Venture Technologies, said,“A123 is delighted that SolidEnergy selected us as a development partner and we look forward to providing them with the ecosystem needed to bring this important technology to market in leading edge products.”

Both companies are rooted at MIT, and the technology was developed at MIT. MIT produces many battery geniuses, doesn’t it? You might remember that an MIT professor created a lithium-ion battery that charges in 20 seconds. MIT is also the birthplace of Ambri, a liquid-metal battery on its way to commercialization.

In the Waltham, Massachusetts development facility, A123 will host SolidEnergy staff members.

The companies plan to jointly produce consumer electronics battery prototypes within the next year, followed by electric vehicle battery prototypes, and SolidEnergy staff will also be hosted in A123’s Waltham, Massachusetts development facility. Test results are expected to be ready for discussion with target customers in the latter part of 2014.

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About the Author

writes on CleanTechnica, Gas2, Kleef&Co, and Green Building Elements. He has a keen interest in physics-intensive topics such as electricity generation, refrigeration and air conditioning technology, energy storage, and geography. His website is:

  • JoanTheSpark

    can’t you use international standard units.. like kilograms instead of pounds?

  • Conrad Clement

    MIT being a government-friendly (Big Oil-friendly) institution, I guess that this announcement is nothing but a vast overstatement to discourage current energy-density leaders from continuing their endeavors… with the weird complicity of a failed company — shame on A123!

    • Bob_Wallace

      I suspect you have no idea how much activity it ongoing in the storage field and how large the storage industry is likely to become.

      To think that an announcement from one company would stop work in the hundreds of other labs is naive.

  • SirSparks

    A123 truly sh** on it’s stock investors by going bankrupt and sellout to the Chinese.
    I believe they have NO right to continue using the name A123 unless they pay those investors for it’s use.

    • Bob_Wallace

      That’s how corporate law is written. When a company can’t continue, is bankrupt, it goes under.

      Any assets, including it’s name, can be sold off in order to recoup as much value as possible for the creditors.

  • Marion Meads

    I thought A123 was bankrupt and have been bought by the Chinese. Are the new majority owners now Chinese?

    • mds

      Yes, Hanergy Group. see mzso greencarcongress link above

      • mds

        Sorry, Hanergy Group is wrong, Wanxiang Group is correct.

        • Marion Meads

          Bummer. It is an irony that after the taxpayers pumped money to A123 and they have bought equipments, they then declared bankruptcy only to be bought by the Chinese for pennies on the dollar. Now the majority Chinese owned factory in America is going to profit more from us. Our government is truly subsidizing the Chinese to fleece us out.

          • Bob_Wallace

            You going to blame the US government for the failures of US businesses to get the job done?

            Time for US companies to quit focusing so much on current quarter profits and giving their CEOs millions of dollars a year while under performing.
            A123 was bought out in an open bidding process. There was no intentional sale to the Chinese, it was just that no US company had the foresight or drive.

          • mds

            Actually, I think our government is subsidizing the rich to sell us out. The up side is high performance batteries will be produced based on this tech breakthrough and from the sound of it this will happen soon due to A123 and Wanxiang scale-up ability.
            Wakeup Amurica!

  • mzso

    On every other place I saw this news they quoted 800 Wh/kg which about for times of the more dense Tesla and Volt batteries.

    • Bob_Wallace

      Yes, 800 Wh/kg is appearing on other sites.

      If they can get anywhere close to 800 Wh/kg this could be the major breakthrough EVs need. That means that one would be able to store vastly more energy with a given amount of material.

      I would guess that manufacturing costs wouldn’t be appreciably different and no expensive unobtainium is being added.

      I find a wide range for the LEAF’s batteries, from 80 to 140 Wh/kg. A 800 Wh/kg battery would mean a 6x to 10x range increase. Take the LEAF’s highway range, 70 miles, bump it up to 200 miles and you’ve got a fully functional ‘drive all day’ EV and a much smaller (cheaper) battery pack. It might be cheaper than an ICE version.

      Deliver something like that to dealer’s showrooms and we’ll switch over.

      (Better yet, just sell them on line and let’s get away from the “Let me talk with my manager” crap.)

      • Ivor O’Connor

        I don’t go in person. Instead I call up and say I will give you X dollars for this car. If you can then you have a deal today. Took me close to 20 dealers before I got one last time… (Had to do my research ahead of time though so I knew what I really should be paying.)

      • Jouni Valkonen

        The energy density of batteries can be some times confusing. In EV battery packs there is also casing, cooling, wires, etc. that add weight. The battery pack weight is for Nissan Leaf 300 kg. Also individual cells has their own energy density. And some times — what is the most confusing — it is only the energy density of the anode. My guess would be that in this case 800 Wh / kg is for the energy density of anode.

        • mzso

          Nope. If it’s only about the anode they’re talking about the anode only. In this news they’re talking batteries.

    • MorinMoss

      Both links says “potentially” – I usually take that to mean “divide by 2”

  • Jouni Valkonen

    Article has unit conversion error: LEAF battery pack weights 300 kg. That is 80 Wh / kg.

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