High‐performance rechargeable Zn‐air batteries with long‐life stability are desirable for power applications in electric vehicles. The key component of the Zn‐air batteries is the bifunctional oxygen electrocatalyst, however, designing a bifunctional oxygen electrocatalyst with high intrinsic reversibility and durability is a challenge. Through density functional theory calculations, it is found that the catalytic activity originated from the electronic and geometric coordination structures synergistic effect of the Fe and Co dual‐sites with metal‐N4 coordination environment, assisting the stronger hybridization of electronic orbitals between Co (dxz, dz2) and OO* (px, pz), thus making the stronger O2 active ability of Co active site. These findings enable to development of a fancy dual single‐atom catalyst comprising adjacent FeN4 and CoN4 sites on N‐doped carbon matrix (FeCo‐NC). FeCo‐NC exhibits extraordinary bifunctional activities for oxygen reduction and evolution reaction (ORR/OER), which displays high half‐wave potential (0.893 V) for the ORR, and low overpotential (343 mV) at 10 mA cm−2 for the OER. The assembled FeCo‐NC air‐electrode works well in the flexible solid‐state Zn‐air battery with a high specific capacity of 747.0 mAh g−1, a long‐time stability of more than 400 h (30 °C), and also a superior performance at extreme temperatures (−30 °C–60 °C).

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Alkaline aqueous batteries such as the Zn j j Ni batteries have attracted substantial interests due to their merits of high energy density, high safety and low cost. However, the freeze of aqueous electrolyte and the poor cycling stability in alkaline condition have hindered their operation in subzero conditions. Herein, we construct a stable aqueous electrolyte with lowest freezing point down to À 90 °C by adding dimethyl sulfoxide (DMSO) as alkaline tolerant antifreezing additive into 1 M KOH solution. Meanwhile, we find the DMSO can also retard Zn anode corrosion and prevent Zn dendrite formation in alkaline condition, which enables the Zn plating/ stripping over 700 h cycle at 1 mA cm À 2 and 0.5 mAh cm À 2 . The fabricated Zn j j Ni battery can endure low working temperature even down to À 60 °C and its dischage capacity retains 84.1 % at À 40 °C, 60.6 % at À 60 °C at 0.5 C. Meanwhile, it can maintain 600 cycles with a specific capacity retention of 86.5 % at À 40 °C at 2 C.