Hi Matt:

The lithium-ion refers the anode construction. In rechargeable Li's, it is ionic Li dissolved into a carbon electrode, whereas in non-rechargeable, it is non-ionic metallic lithium in various forms.

The Cathode is usually an oxide of Cobalt, Manganese, or the newer Phosphate. Environmentalist are liking the Phosphate, since the Cobalt and Manganese are not as friendly to the environment.

The polymer refers to the electrolyte, something like LiCl(original Tadirans had a proprietary thionyl chloride), which is a gel in most of the Li's that have been mentioned in this thread, and can leak, so it has to be contained in a metal container. It also has an organic component(usually some form of tetrachloride) that can burn and explode.

In the Li-ion polymers, the free electrolyte is immobilized(hardened) so there is no need for a metal case to prevent leakage. They are getting 3.8v at high energy densities out of this stuff, and already are sticking it into cell phones and computer packs. You can mold it into the smallest, weirdest shapes if you want. The guys at Sandia and at Oak Ridge have taken this even further with their super thin wafer cells. The military and the auto manufacturers are chomping at the bit.

That was the point I was making initially. It won't be long before those packs will be readily available on the R/C market---the old, heavy, tin can Li packs will become obsolete. Begs the question "Why buy old techno, when new stuff is right around the corner"...wait a few months, put up with those old NiCd or NiMh, and then drop a load of money on the newest stuff..........

You still have to face the problem of limited high current flows in the Li chemistry(impedance), but with this new technology, you can stuff a bunch more capacity into a small foil wrapped package to make up for this deficiency. That's why JetCat is probably interested in the Li-Ion Polymers.

Ain't no engineer! Just passing along info I gleen from my Ham Radio Mags, Scientific American, and other nerdy rags. Photo is just a sample of some of the stuff coming down the line. Actually, don't have to wait too long. I see where Skyborn, FMA and CheapBatteries, and others are already advertising the polymers.

And if all this doesn't put you to sleep, drop over to the batteries section of RCU, or the battery discussion section of E-Zone. Most everything you ever wanted to know about Liths, both batts and chargers has been covered in detail, many times over.

Tom