Originally posted by humy
http://phys.org/news/2015-10-path-ultimate-battery.html
"...Scientists have developed a working laboratory demonstrator of a lithium-oxygen battery which has very high energy density, is more than 90% efficient, and, to date, can be recharged more than 2000 times, showing how several of the problems holding back the development of these devices could be solv ...[text shortened]... an work their way into them interfering with their functionality and so make them less reliable.
Impressive. And I hope this comes to something practical on the market soon.
Originally posted by humyIt says the energy density equals gasoline. Is it theoretically possible for a battery to exceed gasoline in energy density? Even equaling petrol would really put electric cars on the map. You have cars with 300 Km range now, that would approach 3000 Km with such a battery.
http://phys.org/news/2015-10-path-ultimate-battery.html
"...Scientists have developed a working laboratory demonstrator of a lithium-oxygen battery which has very high energy density, is more than 90% efficient, and, to date, can be recharged more than 2000 times, showing how several of the problems holding back the development of these devices could be solv ...[text shortened]... an work their way into them interfering with their functionality and so make them less reliable.
Originally posted by sonhouseI don't see why not. The way a battery works you have oxidation at one terminal and reduction at the other, so it depends on chemistry, but I don't have any intuition as to what the limitations on energy density are. While looking at the relevant Wikipedia pages I came across this, which I'd never heard of before, as humy noted power density isn't the only consideration, longevity is also important and if it's that you want:
It says the energy density equals gasoline. Is it theoretically possible for a battery to exceed gasoline in energy density? Even equaling petrol would really put electric cars on the map. You have cars with 300 Km range now, that would approach 3000 Km with such a battery.
Originally posted by sonhouseNo, I don't think so. They vaguely said "Such a high energy density would be comparable to that of gasoline" without defining what they mean by "comparable" but it certainly doesn't mean "equal"!
It says the energy density equals gasoline. Is it theoretically possible for a battery to exceed gasoline in energy density?
Originally posted by humyBut doesn't the O2 come from just atmosphere? That would reduce the weight right there.
No, I don't think so. They vaguely said "Such a high energy density would be [b]comparable to that of gasoline" without defining what they mean by "comparable" but it certainly doesn't mean "equal"!
I once have worked out that the absolute theoretical maximum energy density for a lithium-sulfur battery, which isn't the same thing as a lithium-oxygen batt ...[text shortened]... ccount the weight of not only the lithium but also the oxygen in the lithium oxide on discharge.[/b]
Originally posted by sonhouseOr add to it.
But doesn't the O2 come from just atmosphere? That would reduce the weight right there.
Originally posted by twhiteheadThat is one of the reasons why I think Mg-S batteries are the long term future; unlike lithium, magnesium is relatively cheap because it is very abundant ( + the theoretical maximum limit to the energy density of Mg-S batteries is far greater than that of, say, lithium-ion batteries, which are often used today + magnesium metal is far less of a hazard if the battery ruptures and the metal is suddenly exposed to air/moisture than lithium -although both Mg and lithium can easily burn, Mg less fiercely so and lithium can much more easily explode! ) .
With cars, although reduced size and weight are desirable, that is not a limiting factor right now. If batteries were exactly the same size and weight as now but either cost half the price ... then it would make electric cars much more desirable. ....