Researchers Discover Way to Increase Life Expectancy of Energy-Dense Lithium Sulfur Batteries by 700%

4 years ago by Eric Loveday 13

Battery Graph

Battery Graph

Lithium-sulfur (Li-S) battery technology has long been claimed to be more energy dense than lithium-ion, but life expectancy of Li-S has never been its strong suit.

That may change soon now that scientists at the Fraunhofer Institute for Material and Beam Technology IWS claim to have come upon a breakthrough that increases the charge cycles of lithium-sulfur batteries by a factor of seven.

Dr. Holger Althues, head of the Chemical Surface Technology group at IWS, had this to say of the breakthrough:

Battery Graph 2

Battery Graph 2

 “During previous tests, the batteries scarcely crossed the 200-cycle mark. By means of a special combination of anode and cathode material, we have now managed to extend the lifespan of lithium-sulfur button cells to 1,400 cycles.”

According to Althues, the anode of the prototype Li-S battery is not made from the usual metallic lithium, but from a silicon-carbon compound instead. This compound, says Althues, is significantly more stable.  Althues describes the issue with previous Li-S designs, saying “In extreme cases, the anode grows to reach the cathode, creating a short circuit and causing the battery to stop working altogether.”

The silicon-carbon compound doesn’t exhibit this sort of behavior, which means the team’s Li-S doesn’t destroy itself over time.

The reason why researchers focus on Li-S is because sulfur, unlike the cobalt that’s widely used in lithium-ion batteries,is available in near unlimited quantities and therefore is significantly cheaper.

There’s still one more hurdle that the researchers are working on before the Li-S battery will be ready for prime time.  Althues says sulfur interacts with the liquid electrolyte, which impairs the battery’s performance and can lead to capacity loss.  To counter this, Althues’ team is using porous carbons, which apparently slow down the process.

Quoting Althues:

“We have precisely altered the pores to allow the sulfur to lodge there, slowing down the rate at which it combines with the electrolyte.”

Battery Graph 3

Battery Graph 3

The researchers at IWS expect lithium-sulfur batteries to have an energy density of up to 600 Wh/kg, but say a more realistic mark is probably 500 Wh/kg.  This, says Althues, would make for a battery with roughly twice the capacity of lithium-ion at the same battery weight.

The next step for the research team is to scale up its prototype to an automotive sized battery pack.

Editor’s Note: The graphs shown throughout this post are not linked to research work done by the scientists at the Fraunhofer Institute for Material and Beam Technology IW.  Rather, they’ve been pulled from various battery-related research works released in the past.

Tags: , , , , , , , , ,

13 responses to "Researchers Discover Way to Increase Life Expectancy of Energy-Dense Lithium Sulfur Batteries by 700%"

  1. zilm says:

    Actually it’s not the only researchers breakthrough for LiS for the last time. I’d like especially this one http://www.nature.com/ncomms/journal/v4/n1/full/ncomms2327.html
    But these doesn’t mean too much. It’s important that different groups of scientists are coming to one result: long lasting LiS batteries. The more different discoveries exist the higher chance it will come to production.
    I hope we will see LiS in production in few years.

  2. David Murray says:

    Yawn.

    This is the 943rd “battery breakthrough” I’ve heard about this year so far.

    1. GeorgeS says:

      Yeh or the 1000th.

  3. Lou Grinzo says:

    Will this be the triple B (Big Battery Breakthrough) we’ve all been salivating over? I have no bloody idea. But I’m convinced that eventually it will happen, and we’ll see a BBB that dramatically changes the EV/PHEV (and possibly wind and solar power) landscape. Why? The potential gain from making the BBB, in terms of dollars and fame, will be immense, and there are many groups both inside and outside of industry working on it.

    1. David Murray says:

      I have no doubt as well. Just look at the difference going from Lead Acid to Nimh to Li-Ion. So yeah, even another incremental step as large as the previous ones will immediately make electric vehicles mainstream vehicles. With the combination of cost/range we have now, they are just barely competitive (and in some cases not competitive at all) with ICE vehicles. Another nudge of 50% or more capacity for the same money would easily push things in the favor of EVs.

  4. Anthony says:

    I’ve been holding out hope for a while now that Li-S is the next major stop on the way to Li-Air and other XX-Air batteries. That hope is becoming a bit more confident every day as I see more developments on Li-S. 1400 cycles is definitely enough for life in an EV or EREV vehicle.

  5. Bonaire says:

    What was the A123 beta-test battery that blew-up in the GM battery lab casing last year? Don’t use that one. But given that it released hydrogen gas to cause the explosion, I just hope these folks do develop a battery that does not off-gas anything dangerous. This is a pretty good breakthrough. What if these could also substitute typical 12V batteries in cars and also in things like forthcoming home-battery banks for standby power or renewable storage. Double/triple the energy density and more cycles. Both will fill these needed niches.

    1. Bonaire says:

      but what is not great is their cycles for this test – only 1400. That’s not great. Some LiFEPO4 packs can cycle 5000-8000 times and still be at 80% capacity.

      1. Cavaron says:

        If they double the range from Li-Ion to LiS – let’s say to 200 miles in a regular EV, then 1400 cycles would equal 280.000 miles. I’m ok with that.

        1. Josh says:

          Also, not all cycles are created equal. A 200 mile pack would do many 80% to 30% discharge cycles in regular use. At least with current technology, two of those cycles do not equal one full cycle of battery fatigue.

    2. zilm says:

      To dramatically improve safety issues (and btw this will improve thermal uniformity) solid electrolyte is needed. There are not much successful research in this area either. I have heard only about one startup and no actual data about its research, only marketing bullshit

  6. greenway says:

    I hope they will be successful with this technology. We will be waiting to have a change to test them. The market needs batteries of this capacity.

  7. When I initially commented I clicked the “Notify me when new comments are added” checkbox
    and now each time a comment is added I get three emails with the same comment.
    Is there any way you can remove me from that service?
    Thanks a lot!