The species dissolved in Fe[Cl.sub.3] activated with [H.sub.2]O are [Fe.sup.2+] [Cl.sup.-.sub.2], [Fe.sup.+] [(OH).sup.-], and [H.sup.+][Cl.sup.-] which indicate that corrosion in Cu foils occur because initially [Cu.sup.+] ion in the presence of [H.sup.+] ion produces cupric chloride (CuCl), and later cuprous chloride
(Cu[Cl.sub.2]) is fully formed by the reaction of CuCl with [Cu.sup.2+] ion [1, 13, 14].
The powders of cuprous chloride (CuCl: >97%) and Cu[Cl.sub.2] (99%, Acros Organics) were thermally dried in vacuum before use.
Ionic liquids were dried at 70 [degrees]C, 12 h in vacuum prior to the electrochemical test; anhydrous cuprous chloride and cupric chloride were used without further processing.
Chen and Sun  reported that copper was electrodeposited on polycrystalline tungsten electrode, platinum electrode, and a glassy carbon electrode in tetrafluoroborate 1-ethyl-3-methyl imidazole (EMIC-B[F.sub.4]) ionic liquids, which joined the cuprous chloride increase the solubility of CuCl; [Cu.sup.+] could be oxidized to [Cu.sup.2+] or reduced to metallic copper; Cu/[Cu.sup.+] redox demonstrated a quasireversible charge transfer process.
In Adams, the patent recited a battery that used a magnesium electrode in concert with a fused cuprous chloride electrode and was activated by adding water as an electrolyte.
If the use of magnesium for zinc and cuprous chloride for silver chloride were merely equivalent substitutions, it would follow that the resulting device--Adams'--would have equivalent operating characteristics.
What distinguishes the substitutions in Adams (eg magnesium for zinc and cuprous chloride for silver chloride) from those in Hotchkiss (clay or porcelain for wood or metal)?