Aqueous rechargeable battery

Abstract

Greater energy densities can be obtained in aqueous rechargeable batteries based on the `rocking chair` principle by the use of certain polymer insertion compounds as an electrode material. Aqueous lithium ion batteries using poly(carbon disulfide) polymer as an anode have energy densities comparable to nickel metal hydride batteries.

What is claimed is: 
     
       1. An aqueous rechargeable battery having a cathode including a first insertion compound with inserted species A, the amount of inserted A in the cathode increasing on discharge and decreasing on recharge of the battery, wherein A is a member of the group consisting essentially of the alkali metals and alkaline earth metals, an anode including a second insertion compound with inserted species A, the amount of inserted A in the anode decreasing on discharge and increasing on recharge of the battery, and an electrolyte comprising a salt of A dissolved in an aqueous solvent mixture, wherein the improvement comprises using of a polymer for at least one of the insertion compounds. 
     
     
       2. A rechargeable battery as claimed in claim 1 wherein the second insertion compound is a polymer. 
     
     
       3. A rechargeable battery as claimed in claim 2 wherein the polymer is a carbon-sulfur based polymer. 
     
     
       4. A rechargeable battery as claimed in claim 3 wherein the polymer is poly(carbon disulfide) having the formula (CS x ) n , wherein x is a number from about 1.2 to 2.33 and n is a number greater than or equal to 2. 
     
     
       5. A rechargeable battery as claimed in claim 4 wherein A is lithium. 
     
     
       6. A rechargeable battery as claimed in claim 5 wherein the first insertion compound is a lithium manganese oxide spinel Li y  Mn 2  O 4 , wherein y is a number in the range from 0 to about 2. 
     
     
       7. A rechargeable battery as claimed in claim 5 wherein the pH of the electrolyte is greater than 7.