GB794970A - Electric current-producing cell and method of producing current using the same - Google Patents

Abstract

794,970. Batteries. CORSON, Inc., G. & W. H. Dec. 24, 1953, No. 35866/53. Class 53. An electric cell having two separate electrolytes comprises an anolyte and a catholyte each consisting of a salt dissolved in anhydrous liquid ammonia, the cation of the salt in the anolyte being the metal of the anode and the cation of the salt in the catholyte being ammonium or a metal which develops a potential at least 0.75 volts less than the anode metal, as measured in liquid ammonia. The anode 3 and anolyte 10 are separated from the annular cathode 6 and catholyte 11 by a permeable partition 9. The anode may be of Li, Na, K, Cs, Rb, Ca, Sr, Ba, Mg, Zn, Al, Be or Mn, and in one example a lithium anode in the form of a paste with ammonia is described with lithium thiocyanate in the anode compartment. In another example the anode is of metallic sodium with sodium thiocyanate in ammonia as an anolyte, and in both cases the catholyte consists of ammonium thiocyanate in ammonia. The cathode may be of Pt, C, B, Zr, W, or Ta or may correspond to the cation of the catholyte, where a metal salt is used. With NH 4 as the cation of the catholyte, H 2 is released during discharging and N 2 during changing. The anolyte may comprise a perchlorate, fluoborate, cyanate, nitrate or nitrite. A minor amount of a liquid amine (e.g. methylamine, ethylamine or pyridine) or of methyl cellulose may be added for some purpose such as reducing sludge. To avoid spilling the electrolytes may be mixed with an absorbent mass such as glass fibre. The lithium cell produces a potential of about 2¢ volts, with a current density of 20 mA. per square inch, but other cells produce potentials up to 4 volts. The cell is especially suitable for low-temperature operation, with improved efficiency, but can be used up to 50‹ C. if refrigerated or under pressure in a strong jacket. The freezing point of liquid ammonia (- 77‹ C.) is lowered by the electrolyte salt and this increases the low temperature range of the cell. Normally the electrolytes are separated only by a semipermeable diaphragm but for storage one may be in a sealed capsule.