Turquoise Battery Project Info
 by Craig Carmichael
January 2012


   My first idea in this endeavor was simply to figure out a way to make nickel-metal hydride alkaline batteries at home.
   But as I explored I learned more, and I decided that what's been done in the battery field isn't all it should be. I set out to create something either cheaper or better or both. In particular, I discovered there had been no advances in salty electrolyte batteries since the standard manganese-zinc (so-called "carbon-zinc") dry cell in the 1880's.
   It took me 2-1/2 years to figure out why: every metal I tried for a structure for the positive electrode corroded away. Carbon and only carbon works. (Well, possibly some pricey stuff like platinum might work. I didn't try that since it violated my "economical" objective.) That's why standard dry cells have a hardened carbon rod for the positive terminal post, touching graphite powder that makes the manganese dioxide powder more conductive.
   Then it took me another year to figure out a good solution: I created "grafpoxy": a 1 to 1 (by weight) mixture of epoxy and fine graphite powder, to coat "whatever" electrode current collector and terminal metal with. The epoxy protects the metal parts, and the graphite makes it sufficiently electrically conductive for good current flow. I still use graphite along with other means to improve conductivity within the "electrode briquettes" - the electrode powders compressed into a solid block.

   Over a century later, salty (potassium chloride) batteries using grafpoxy coatings can now be even more economical than alkaline (potassium hydroxide) cells with their nickel coatings, and have the potential for high currents. Some alkaline positive electrodes like nickel (nickel oxyhydroxide) work the same in salty fluid but with higher voltages (+1.0 volt instead of +.5 volts); others like vanadium (vanadium pentoxide) work only in salt. Zinc also works about the same, with a bit lower voltage. Other negative elements are also worth trying. Selecting good elements, cells with voltages around two volts seem to be the norm.

   I've done my best to make them makeable at home, but I fear the processes as far as I've taken them are rather exacting and tedious. As far as I've gone, it's all detailed in How to Make Economical, Green, High Energy Batteries under "Construction Manuals" on this web site.