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Superior Anode For Lithium-Ion Batteries Developed
RogerRoast writes "The anode is a critical component for storing energy in lithium-ion batteries. The Berkeley Lab (D.O.E) has designed a new kind of anode that can absorb eight times the lithium of current designs, and has maintained its greatly increased energy capacity after over a year of testing and many hundreds of charge-discharge cycles. According to the research published in Advanced Materials they used a tailored polymer that conducts electricity and binds closely to lithium-storing silicon particles, even as they expand to more than three times their volume during charging and then shrink again during discharge."
Energy capacity (assuming constant voltage) is linear with stored charge.. stored charge is linear with quantity of active species, which is going up by a factor of 8, so I'd guess about 8 times.
Voltage is never constant under high discharge rates... lead acid "car" batteries are famous for covering their plates temporarily with gas (h2) and all batteries dump some fraction of their capacity into their internal resistance. For a good example try pulling 10 amps out of a giant deep cycle marine battery, then outta a nicad C size cell, then outta a pre-alkaline, pre-heavy duty zinc C size cell (think radio shack battery of the month club red battery).
expand to more than three times their volume during charging and then shrink again during discharge
Well, that's fairly terrifying word choice to anyone who did extreme stuff with prior battery techs. Expanding lead acid cell means the vent is clogged and you're about to get a large dose of flammable H2, corrosive electrolyte, and splintering plastic. Expanding lithium means its about to go kaboom. "Expand" is not a cool choice of words around battery people. Call it "volumetrically challenged" or something.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
I'd guess about 8 times.
If that's true, and even if it only works out to six times in production then it almost solves the car battery problem. We can get about 100 miles with existing batteries and 600 miles is about as far as a normal person would want to drive in a day (ie. average 60mph for ten hours).
(I say "almost" because of the following posts...)
No sig today...
There are many improved versions of the Li-Ion battery that last longer (as in more cycles) but they never seem to reach the market. Yeah feck it you can buy loose 18650 LiFePO4 cells and even lithium based supercapacitors but name one phone or laptop a normal person can easily buy with anything other than the bog standard 400-500 cycle-then-dead Li-Ion battery?
I expect that the reason for this is quite sinister - Li-Ion batteries are used to enforce planned obsolescense, which is why standard cells are often packed into an overpriced proprietary plastic casing before sale. Manufacturers of consumer electronics don't want batteries that are still good after thousands of cycles. Apple also deserves a mention for pioneering the idea of packing the battery into the hard to open case of the phone/laptop itself, forcing 99% of the people who own these products to buy a new one as soon as the battery dies.