Storage batteries containing zinc halide in an aqueous solution of the type having a soluble cathode and a dissolved anode

Abstract

An improved reversible electric cell of the type which includes a soluble metal cathode, a chemically nonreactive electrode and an electrolyte comprising an aqueous solution of a metal halide is disclosed. The electrode is provided with open channels or grooves in which a dispersion, of paste-like consistency, is disposed. The dispersion or mixture comprises an inert conducting powder and an alkylammonium perchlorate. The alkylammonium perchlorate combines with the halogen released upon charging to form an addition product in a solid state. This prevents the halogen from being dissolved in the electrolyte during the charging cycle which would corrode soluble metal cathode and discharge the cell.

What is claimed is: 
     
       1. A reversible cell of the type which includes a zinc cathode, a chemically non-reactive electrode and an electrolyte comprising an aqueous solution of zinc bromide, the improvement in which the said electrode is in contact with said zinc bromide solution and with a conductive dispersion soaked in alkylammonium perchlorate which captures the bromine that is formed during the charging process, said electrolyte being capable of being removed from the cell when the cell is not in use and of being returned to the cell when the cell is in use. 
     
     
       2. A reversible electric cell which comprises a zinc cathode, an electrolyte formed of an aqueous solution of zinc bromide, a chemically non-reactive electrode which carries a dispersion of powdered graphite soaked in a salt, said salt selected from the group consisting of tetramethylammonium perchlorate and tetrabutylammonium perchlorate, said graphite electrode being in contact with said electrolyte and with said dispersion, said dispersion absorbing bromine during charging and restoring bromine during discharging. 
     
     
       3. An improved electric cell comprising a soluble metal cathode, selected from the group consisting of zinc and cadmium said metal having a high electromotive value; a chemically non-reactive solid positive electrode and an electrolyte formed of a solution of a halide selected from the group consisting of chlorine, bromine, and iodine, of said cathodic metal; said positive electrode having open channels in lateral contact with said electrolyte and having disposed therein a homogeneous conductive dispersion or suspension of an inert conductive powder and an alkylammonium perchlorate selected from the group consisting of tetramethylammonium perchlorate, tetrabutylammonium perchlorate, tetraethylammonium perchlorate, and cetiltrimethylammonium perchlorate. 
     
     
       4. The electric cell in accordance with claim 3 wherein said soluble cathodic metal is zinc, said solid positive electrode is graphite, said halide is bromine and said alkylammonium perchlorate is tetramethylammonium perchlorate. 
     
     
       5. The reversible electric cell in accordance with claim 3 wherein said alkylammonium perchlorate is tetramethylammonium perchlorate and wherein said conducting substance in powdered form is powdered graphite. 
     
     
       6. The reversible electric cell in accordance with claim 5 wherein said dispersion further includes charcoal. 
     
     
       7. The reversible electric cell in accordance with claim 3 wherein said open channels are wedge-shaped. 
     
     
       8. The reversible electric cell in accordance with claim 3 wherein said open channels are substantially L-shaped. 
     
     
       9. A battery including a series of reversible electric cells, said cells each comprising a zinc cathode, and a chemically non-reactive positive electrode, said positive electrode having a series of open channels therein, said channels being in lateral contact with an electrolyte formed of an aqueous solution of a zinc halide, said zinc halide selected from the group consisting of zinc bromide and zinc iodide, said channels further being in intimate contact with a paste-like mixture comprising an alkylammonium perchlorate and a conductive powder, said alkylammonium perchlorate in said mixture serving to combine with free halide during the charging cycle of said battery and form a solid addition product thereof and means for recycling said electrolyte to and from said series of cells for said battery. 
     
     
       10. The battery in accordance with claim 9 wherein said alkylammonium perchlorate is tetramethylammonium perchlorate and said conductive powder is powdered graphite.