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A room temperature Li2O-based lithium-air battery enabled by a solid electrolyte

science.org

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Re: A room temperature Li2O-based lithium-air battery enabled by a solid electrolyte

#31

Post by cyberax »

fuzzfactor wrote: post #28
Xamayon wrote: post #7

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!

If this comes through it may boost performance to have a turbocharger for better forced air intake. Or with a tank of pure oxygen, have the EV act like it was gasoline engine on nitrous oxide. Somebody should calculate a ballpark figure for the number of grams or kilos of oxygen that would be needed per mile for an average vehicle.

> If this comes through it may boost performance to have a turbocharger for better forced air intake.

No it won't. At most, the battery might need a small fan. Turbochargers are needed for regular cars because internal combustion engines just suck.

Re: A room temperature Li2O-based lithium-air battery enabled by a solid electrolyte

#32

Post by DennisP »

cyberax wrote: post #30
Matterless wrote: post #12

/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?

If an EV goes 400 miles on a single charge, then you're looking at 400000 miles of total range! That's absolutely acceptable.

And at more than double the energy density of today's EV batteries, its range could be considerably longer.

Re: A room temperature Li2O-based lithium-air battery enabled by a solid electrolyte

#33

Post by BWStearns »

adrian_b wrote: post #14
aetherspawn wrote: post #10

Does it use external air? Would this technically make it a fuel cell and not a battery, since some of the reactants are discarded :)

Not really. In a fuel cell the reaction products are discarded (the reactants cannot be discarded, as they are needed for the reaction to take place). In a metal-air battery, air from the atmosphere is taken into the battery and the oxygen from it becomes bound to the metal, in a metal oxide. So unlike for a fuel cell, where the vehicle becomes lighter after the fuel is consumed and the reaction products are discarde…

Interesting. So if it was used for aviation then your takeoff weight would be lower than your landing weight. That'll be counterintuitive.

Re: A room temperature Li2O-based lithium-air battery enabled by a solid electrolyte

#34

Post by bagels »

thot_experiment wrote: post #15
norrsson wrote: post #5

Earlier quoted context omitted.

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

I think your point still stands but modern engines cluster toward the higher end of that range and some do exceed the 30% efficiency mark, hybrid drivetrains can approach 40%.

Not that any of the tech is practical for every day cars or how they're used, but F1 engines with the multiple energy recovery systems are up to 52% efficient if they are to be believed (we'll ignore the rules subterfuge around tricking the fuel sensors, injecting oil, and who knows what else).

Re: A room temperature Li2O-based lithium-air battery enabled by a solid electrolyte

#36

Post by aitchnyu »

fuzzfactor wrote: post #28
Xamayon wrote: post #7

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!

If this comes through it may boost performance to have a turbocharger for better forced air intake. Or with a tank of pure oxygen, have the EV act like it was gasoline engine on nitrous oxide. Somebody should calculate a ballpark figure for the number of grams or kilos of oxygen that would be needed per mile for an average vehicle.

Transmission makers (ZK), turbocharger makers, who else are going to survive EV migration?

Re: A room temperature Li2O-based lithium-air battery enabled by a solid electrolyte

#37

Post by fpoling »

thot_experiment wrote: post #15
norrsson wrote: post #5

Earlier quoted context omitted.

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

I think your point still stands but modern engines cluster toward the higher end of that range and some do exceed the 30% efficiency mark, hybrid drivetrains can approach 40%.

Indeed. Tesla Model 3 consumes about 50MJ of battery energy per 100 km. Toyota Prius consumes about 4.5 liters of gasoline. That gives roughly 150 MJ. So a electrical car consumes 3 times less or about 33% of energy of one of the best hybrid drivetrain.

Re: A room temperature Li2O-based lithium-air battery enabled by a solid electrolyte

#38

Post by thomasmg »

BWStearns wrote: post #33
adrian_b wrote: post #14

Earlier quoted context omitted.

Not really. In a fuel cell the reaction products are discarded (the reactants cannot be discarded, as they are needed for the reaction to take place). In a metal-air battery, air from the atmosphere is taken into the battery and the oxygen from it becomes bound to the metal, in a metal oxide. So unlike for a fuel cell, where the vehicle becomes lighter after the fuel is consumed and the reaction products are discarde…

Interesting. So if it was used for aviation then your takeoff weight would be lower than your landing weight. That'll be counterintuitive.

Unless if the spent battery calls are released during the flight, via parachute, to be recharched later.

We currently call spent batteries "empty" but in this case spent = "full" (of oxygen).

Re: A room temperature Li2O-based lithium-air battery enabled by a solid electrolyte

#39

Post by jillesvangurp »

timerol wrote: post #4
fs_tab wrote: post #2

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.

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 th…

Especially when considering that most of that 13 Wh/kg for petrol is typically delivered as waste heat. You can get a decent estimate of how bad it is comparing miles per kwh for an EV to miles per gallon for a typical petrol car. It's about 3-4 miles per kwh vs. about 20 miles per gallon. EVs just use their kwh a lot more efficiently than petrol cars. Because batteries and electrical motors are just really efficient.

An 11 wh/kg battery would result in a battery that delivers about 5-6 times more miles per kg of battery than petrol. You get weight parity around 3-4 kg. If you factor in the weight of the engine (they can be quite heavy) it gets a little better. Of course the weight matters far less than people think. The amount of energy needed to move a vehicle does not necesseily scale linearly with weight of the vehicle. Which is why a heavy cyber truck and much lighter / smaller EVs can have miles per kwh metrics that aren't that far apart. Same with petrol cars. Halving the weight doesn't given them twice as much range. Heavy batteries are not that big of a deal. Unless you put them in a plane. Weight matters a lot in planes.

So, a battery like this would be amazing news for battery electric planes that currently fly with 200-300 wh/kg batteries (at best). 11kwh/kg would be a 70x improvement in energy density. That's a lot of range. Even a small fraction of that would be a massive improvement. 700wh/kg more than doubles the range already.

I think we'll see batteries break 1kwh/kg next decade or so. 500 wh/kg is already on its way to production. So, a doubling is only a modest step up. At 1kwh/kg, most GA flight will become electric. 3-6 hours of range with dirt cheap electricity turns a 100$ hamburger into a Starbucks coffee run. That's game over for ICE engines in small planes.

Re: A room temperature Li2O-based lithium-air battery enabled by a solid electrolyte

#40

Post by jillesvangurp »

fpoling wrote: post #37
thot_experiment wrote: post #15

Earlier quoted context omitted.

I think your point still stands but modern engines cluster toward the higher end of that range and some do exceed the 30% efficiency mark, hybrid drivetrains can approach 40%.

Indeed. Tesla Model 3 consumes about 50MJ of battery energy per 100 km. Toyota Prius consumes about 4.5 liters of gasoline. That gives roughly 150 MJ. So a electrical car consumes 3 times less or about 33% of energy of one of the best hybrid drivetrain.

Is that fresh out of the factory or after a few years of service? I think a lot of the metrics around hybrids are a bit optimistic. In the same way that official metrics for EV ranges are usually a bit more than is realistic.

Hybrids running on battery are about as efficient as an EV. When you enter the highway, they turn into ordinary ICE engines. If you use your prius exclusively for traffic in your neighborhood, you only use petrol to charge the battery, which is efficient and about as good as it gets with a hybrid. Unless you can plug it in of course. It won't use any petrol at all in that case.

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