interesting new LiOn Technology

[Papuga]

http://i.engadget.com/2010/08/11/researchers-make-progress-with-better-safer-aqueous-lithium-ion/

This looks pretty promising. If they can improve the capacity it may be the next best battery technology.

 

[Battery Guy]

http://i.engadget.com/2010/08/11/researchers-make-progress-with-better-safer-aqueous-lithium-ion/

This looks pretty promising. If they can improve the capacity it may be the next best battery technology.

Don't mean to rain on the parade, but I looked into this and did a couple back-of-the-envelope calculations.

To have an aqueous lithium-ion battery, you need to keep the voltage at or below ~1.2V vs lithium to prevent electrolysis of water. These "new" lithium-ion cells use an iron phosphate cathode and a titanium phosphate anode, providing a voltage in the 1.0-1.2 V range. This combination of cathode and anode would have a volumetric capacity equivalent to a typical A123 phosphate cell, with about 1/3 the voltage. That gives this new, aqueous lithium-ion cell an energy density somewhere between lead-acid and NiCd.

That being said, there is a huge market for cheap, high cycle life batteries for reserve power applications where the size and weight of the battery is not very important. There is a big push to replace lead-acid for these applications. However, for portable applications, this technology is not appropriate unless you want to carry your flashlight battery in a back pack.

But don't get disappointed. There is a technology out there that would really kick butt for flashaholics: zinc-silver. That technology has higher power and nearly 50% higher energy density compared to lithium-ion. My fingers are crossed for ZPower, hoping that they can pull this off.

Cheers,
BG

 

[Ray_of_Light]

Hi BG,

in year 1990 I had a "dream flashlight" built with a zinc-silver battery. The battery was in the handle of the flashlight, and the bulb was a PAR 30 W (non-replaceable). The runtime was one hour.
The flashlight costed around $ 500 IIRC, and in the U.S. it was sold on the Mc-Master Carr catalog. The manufacturer promised 200 full cycle from the battery.
Well, not one resisted the test of time. As to be expected, the high-self discharge and leak-prone attitude of the battery were the problem...
The Zn-Ag has (or better, it had) the same problem plaguing the actual Ni-Zn batteries; mainly due to the attitude of the zinc in alkaline environment, and to the lack of a water reforming cycle in the battery.
I really would like to tap into the power of Zn-Ag batteries; as you say, it would be a "dream" battery for flashaholics. But, after many years of experience I learned the hard way NOT to trust any battery, primary or secondary, which contains zinc.

Regards

Anthony