[HN Gopher] A room temperature Li2O-based lithium-air battery en...
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       A room temperature Li2O-based lithium-air battery enabled by a
       solid electrolyte
        
       Author : fs_tab
       Score  : 33 points
       Date   : 2024-12-12 20:14 UTC (2 hours ago)
        
 (HTM) web link (www.science.org)
 (TXT) w3m dump (www.science.org)
        
       | fs_tab wrote:
       | From the abstract: A lithium-air battery based on lithium oxide
       | (Li2O) formation can theoretically deliver an energy density that
       | is comparable to that of gasoline.
        
         | shsudhdudi wrote:
         | Li Air battery for the wings??
        
         | timerol wrote:
         | This particular Li2O battery is a little under 700 Wh/kg, with
         | the theoretical maximum being 11k Wh/kg, compared to gasoline's
         | 13k Wh/kg. It's an incredible accomplishment that they have
         | managed to get such a reaction reasonably stable. Minor
         | improvements to the battery cited in the paper would be beyond
         | the theoretical limits of existing commercial lithium
         | chemistries.
         | 
         | > The results shown in fig. S9 indicate that this solid-state
         | Li-air battery cell can work up to a capacity of ~10.4 mAh/cm2,
         | resulting in a specific energy of ~685 Wh/kgcell. In addition,
         | the cell has a volumetric energy density of ~614 Wh/Lcell
         | because it operates well in air with no deleterious effects
         | (supplementary materials, section S6.3)
        
           | norrsson wrote:
           | Usual disclaimer regarding the energy density of gasoline:
           | current gasoline engines have an efficiency of 10-30% while
           | EVs are around 90%.
           | 
           | So to reach similar kWh/g we're looking at ~3k Wh/kg
        
             | lukevp wrote:
             | Is there a similar volumetric equivalent measurement or is
             | it all about energy density by weight? Like, if the
             | batteries are lightweight but massive, that would also be a
             | bit of a problem since the structure to safely transport a
             | large volume could be expensive and heavy.
        
               | sn0wf1re wrote:
               | Looks like the created cell is 614 Wh/L from the above
               | comment. Gasoline is ~2.2kWh/L [0]. So my take is that
               | even with the created cell the density is not going to be
               | an issue with car or grid batteries -- only <4 times the
               | size even at this non-theoretical cell. Who knows how the
               | packs will be configured though as I am sure airflow will
               | be a design consideration when making larger packs.
               | 
               | [0] This uses the 3kWh/kg that was provided above and a
               | density of gasoline of .75g/mL                   units
               | You have: 0.7429 g/mL * 3 kWh/kg         You want: kWh/L
               | * 2.2287
        
             | andy_ppp wrote:
             | Does the engine and drive train weight make these
             | calculations even better for electric vehicles?
        
               | TOMDM wrote:
               | I feel like a good like to like comparison would be the
               | density of battery + motors compared to the density of
               | fuel tank, engine and drive train.
        
       | Xamayon wrote:
       | If it can be made small enough for use in mobile devices, I
       | wonder whether the need for air/oxygen might require compromising
       | on water-tightness. Would an oxygen permeable waterproof membrane
       | allow enough through for operation? It would be interesting if
       | instead of just for cooling, future high powered devices might
       | also need a fan to feed the battery!
        
       | aetherspawn wrote:
       | Does it use external air?
       | 
       | Would this technically make it a fuel cell and not a battery,
       | since some of the reactants are discarded :)
        
       | Matterless wrote:
       | /Up to 1000 charge cycles/ is a big damper on the excitement, for
       | me. Does anyone know if a limitation like that is inherent to the
       | chemistry here or is this something that they could potentially
       | (hopefully, vastly) surpass?
        
         | bryanlarsen wrote:
         | That's a comparable rating to the NMC Lithium cells used in an
         | electric car, yet an EV can typically get > 200,000 miles from
         | their cells. A charge cycle is defined as 0% -> 100% -> 0%. If
         | you never do that, you get a lot more effective charge cycles.
        
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       (page generated 2024-12-12 23:00 UTC)