Non-aqueous solvents, electrodeposition and electrodissolution of metals therein andelectrochemical cells containing solutions of salts in non-aqueous solvents as electrolyte

摘要

Alkali metals are electrodeposited from a solution of a salt of the metal to be deposited which is inert to sulphur dioxide dissolved in a mixture of sulphur dioxide and an organic solvent having no acidic hydrogen atoms and containing an element having at least one unshared electron pair, in relative amounts sufficient to provide mutual solubility and a conductivity of at least 5 x 10-5 ohm-1 cm-1 at 22 DEG C. Cathodes may be of alkali and alkaline earth metals, Mg, Cu, Ag, Cd, Hg, Al, Ni, Pt, which may be in foamed or sintered form, carbon, graphite or silicon, alloys, amalgams, or mixtures of metals and conductive non-metals, e.g. stainless steels, nickel alloys, compressed metal and carbon. The anode is formed of the metal to be deposited alone or coated over a conductive base. The alkali metal salt may include as anion radicals derived from any of the common carboxylic acids, or p-toluene sulphonic acid, or may be an alkali metal chloride, bromide, cyanide, cyanate, thiocyanate, sulphide, sulphite, selenide, selenate, sulphanate, nitrate, dicyanamide, tricyanomethide, hexafluoroarsenate, -phosphate, or-silicate, monofluoroacetate, or chloro- or bromo-aluminate. Suitable organic solvents are provided by triallkyl borates; boronic or borinic acid esters; tetraalkyl silicates; alklylakoxyl silanes; amino-ethers including N-methyl morpholine; tertiary amines; nitroalkanes; alkyl nitriles; trialkyl hydroxylamines; dialkyl amides; lactams such as N-methylpyrollidinone; tetraalkyl ureas; acetals; ketals; monocarboxylic acid esters; esters of ortho acids such as trimethyl orthoformate and tetramethyl orthocarbonate; lactones; dialkyl and alkylene carbonates; monoethers; cyclic ethers; polyethers; monocarboxylic acid anhydrides; dialkyl sulphates, sulphites, or sulphinites; alkylene sulphites; and alkyl sulphonates; or mixtures of these compounds. Typically sulphur dioxide is rubbed into a cell made of polythene, polypropylene, PTFE or glass provided with an inert atmosphere of argon, xenon or helium containing dimethyl or ethylene sulphite; propylene ethylene or dimethyl carbonate; or acetonitrile and a lithium salt until the solvent is saturated with SO2. Electrolysis is then effected using a lithium amalgam or lithium ribbon anode and a nickel cathode on which lithium is deposited.