Long life sealed alkaline secondary batteries

A rechargeable battery comprising:

• a battery container sealed against release of gas up to at least a threshold gas pressure;
• a volume of an aqueous alkaline electrolyte at least partially filling the battery container to an electrolyte level;
• a positive electrode containing positive active material and at least partially submerged in the aqueous alkaline electrolyte;
• an iron negative electrode at least partially submerged in the aqueous alkaline electrolyte, the iron negative electrode comprising iron active material;
• a separator at least partially submerged in the aqueous alkaline electrolyte provided between the positive electrode and the iron negative electrode;
• and
• an auxiliary oxygen gas recombination electrode electrically coupled to the iron negative electrode, the auxiliary oxygen gas recombination electrode ionically coupled to the aqueous alkaline electrolyte, and the auxiliary oxygen gas recombination electrode exposed to a gas headspace in the battery container above the aqueous alkaline electrolyte gas pathway.