Battery comprising a coated iron anode

Abstract

The present invention provides one with a battery having an iron anode, e.g., a Ni—Fe battery, having improved performance characteristics. The battery uses a particular electrolyte and/or battery separator. The resulting characteristics of efficiency, charge retention and cycle life are much improved over such batteries in the prior art.

What is claimed is: 
     
         1 . A battery comprising a cathode, an iron anode comprised of a single layer of a conductive substrate coated on at least one side with a coating comprising an iron active material and a polyvinyl alcohol binder, an electrolyte comprised of sodium hydroxide, lithium hydroxide and sodium sulfide, and a polymeric battery separator. 
     
     
         2 . The battery of  claim 1 , wherein the cathode is a nickel or manganese cathode. 
     
     
         3 . The battery of  claim 1 , which is a sealed battery. 
     
     
         4 . The battery of  claim 1 , wherein the battery separator is made of a polyolefin. 
     
     
         5 . The battery of  claim 1 , wherein the substrate is coated on both sides. 
     
     
         6 . The battery of  claim 1 , comprising an iron anode and with the battery exhibiting a specific energy of at least about 105 watt hours/kg. 
     
     
         7 . The battery of  claim 1 , comprising an iron anode and with the battery exhibiting an energy density of at least about 183 watt hours/liter. 
     
     
         8 . The battery of  claim 1 , comprising an iron anode and with the battery exhibiting a specific power of at least about 2100 watts/kg. 
     
     
         9 . The battery of  claim 1 , comprising an iron anode and with the battery exhibiting a power density of at least about 3660 watts/liter. 
     
     
         10 . The battery of  claim 1 , comprising an iron anode and with the battery exhibiting a watt hour efficiency of at least about 95%. 
     
     
         11 . The battery of  claim 1 , comprising an iron anode and with the battery exhibiting a charge retention, measured as capacity at 28 days 20° C., of at least about 95%. 
     
     
         12 . The battery of  claim 1 , comprising an iron anode and with the battery exhibiting a cycle life of at least about 10,000 cycles. 
     
     
         13 . The battery of  claim 1 , the iron anode further comprising sulfur. 
     
     
         14 . The battery of  claim 1 , wherein the sodium sulfide concentration in the electrolyte is about 2 wt % based on the weight of the electrolyte.