Nickel-iron battery with high power
The present invention provides one with a Ni—Fe battery exhibiting enhanced power characteristics. The battery uses a particular electrolyte comprising sodium hydroxide, lithium hydroxide, and sulfide. The use of the sodium hydroxide based electrolyte with the iron anode in the battery has been found to enhance the performance characteristics of the battery. The resulting characteristics of specific power and power density are much improved over conventional Ni—Fe batteries.
1. A battery, comprising:
a nickel cathode;
an iron anode comprising an iron active material that is metal iron or an iron oxide material, sulfur and a polyvinyl alcohol binder; and
an electrolyte comprising 6 to 7.5 M sodium hydroxide, 0.5 to 2.0 M lithium hydroxide, and 1-2 wt % sodium sulfide based on the weight of the electrolyte,
with the battery exhibiting a power density of at least about 3660 watts/liter and a specific power of at least about 2100 watts/kg.
2. The battery of claim 1 , further comprising a polyolefin battery separator.
3. The battery of claim 1 , which is a sealed battery.
4. The battery of claim 1 , wherein the iron anode is comprised of a single layer of a conductive substrate coated on at least one side with a coating comprising the iron active material and the binder.
5. The battery of claim 4 , wherein the substrate is coated on both sides.
6. The battery of claim 1 , further exhibiting a specific energy of at least about 105 watt hours/kg.
7. The battery of claim 1 , further exhibiting an energy density of at least about 183 watt hours/liter.
8. The battery of claim 1 , further exhibiting a watt hour efficiency of at least about 95%.
9. The battery of claim 1 , further exhibiting a charge retention, measured as capacity at 28 days 20° C., of at least about 95%.
10. The battery of claim 1 , exhibiting
a specific energy of at least about 105 watt hours/kg;
an energy density of at least about 183 watt hours/liter;
a watt hour efficiency of at least about 95%; and
a charge retention of at least about 95%.
11. The battery of claim 1 , exhibiting a cycle life of at least about 10,000 cycles.