Reversible electrodeposition device with ionic liquid electrolyte

A reversible electrodeposition device for controlling the propagation of electromagnetic radiation, comprising:

• a first electrode which is substantially transparent to the radiation;
• a second electrode;
• and
• an ionic liquid electrolyte disposed between and in electrical contact with said first and second electrodes, said ionic liquid electrolyte comprising:
• ions of an electrodepositable metal selected from the group consisting of silver, copper, tin, zinc, palladium, bismuth, cadmium, mercury, indium, lead, antimony, thallium and alloys thereof,
• heterocyclic organic cations selected from the group consisting of N-methylpyrrolidinium, pyrrolidinium, 1-ethyl-3-methylimidazolium, 1-N-butylpyridinium, 2-methyl-1-pyrrolinium, 1-ethyl-midazolium and mixtures thereof, and
• complexing anions selected from the group consisting of chloride, bromide, iodide, cyanide and thiocyanate,
• such that a negative electrical potential applied to the first electrode relative to the second electrode tends to cause metal to be electrodeposited from the electrolyte onto the first electrode, and
• such that a positive electrical potential applied to the first electrode relative to the second electrode tends to cause deposited metal to be dissolved from the first electrode,
• wherein the amount of deposited metal subsisting on the first electrode affects the propagation of radiation by the device.