Considering the outstanding bifunctional catalytic activity of FeNi-NC@MWCNT, its practical performances in primary and rechargeable Zn-air batteries have been evaluated with customdesigned cells. As schematically illustrated in Figure , a customized two-electrode ZAB was assembled utilizing an air cathode loaded with FeNi-NC@MWCNT as catalyst. A zinc metal plate was used as anode. The electrolyte was 6.0 M aqueous KOH containing 0.2 M Zn(OAc)2. As references, ZABs using FeNi-NC and a mixture of commercial Pt/C + IrO2 (with mass ratio of 1:1) as cathode catalyst were fabricated. As shown in Figure , the discharge polarization curves (at j = 260 mA cm -2 ) show that the ZAB catalyzed by FeNi-NC@MWCNT exhibits a maximum power density of 218.3 mW cm -2 which is considerably higher than for Pt/C + IrO2 (176.6 mW cm -2 ). The ZAB based on FeNi-NC@MWCNT also delivers a stable open-circuit voltage (OCV) of 1.44 V with no obvious changes over 1 h (Figure ), which is marginally higher than for FeNi-NC (1.41 V) and Pt/C + IrO2 (1.39 V). These observations are in line with the catalytic activities in three-electrode configuration reported above. The inserted picture in Figure shows the LED display (1-5 V) was successfully lit up with the FeNi-NC@MWCNT based ZAB, demonstrating the practical application of this catalyst. As shown in Figure , the FeNi-NC@MWCNT containing ZAB shows a specific capacity of 781.7 mAh g -1 (normalized to the mass of consumed Zn), which outperforms the capacities of a Fe-NC based ZAB (740.8 mAh g -1 ) and Pt/C based ZAB (763.2 mAh g -1 ). The output voltage of the FeNi-NC@MWCNT ZAB is approx. 1.18 V, which is superior to FeNi-NC (1.13 V) and Pt/C (1.16 V). Furthermore, as demonstrated in Figure (SI), the primary ZAB with FeNi-NC@MWCNT catalyst was discharged under galvanostatic conditions (15 mA cm -2 ) for more than 21 h without a noticeable voltage drop. Figure shows the remarkable discharging rate capacity and durability of FeNi-NC@MWCNTbased ZAB at various discharge current densities ranging from 5 to 50 mA cm -2 , no significant voltage loss was observed with increasing discharge current. Notably, the initial and final discharge voltage of the FeNi-NC@MWCNT-based ZAB at 1 mA cm -2 remain unchanged (1.25 V), suggesting a robust long-term discharge capacity. To further investigate the rechargeability of the ZABs, the longterm cycling stability of the ZABs catalyzed by FeNi-NC@MWCNT was tested by continuous galvanostatic charge/discharge at a current density of 15 mA cm -2 . The duration of each cycle was set to 1 hour (0.5 h for discharging and 0.5 h for subsequent charging) with an initial charge voltage of 1.8 V and discharge voltage of 1.15 V, respectively. The ZABs with commercial Pt/C +IrO2 were examined under identical conditions for comparison. As shown in Figure , the ZAB assembled with FeNi-NC@MWCNT exhibits a higher discharge current density and a lower charge/discharge voltage gap compared to the ZABs based on Pt/C+ IrO2. In addition, the round-trip efficiency of the ZABs were calculated based on the charge/discharge voltage gap of the second cycle. The ZAB with FeNi-NC@MWCNT exhibits a high round-trip efficiency of 73% (SI, Figure ), surpassing that of the Pt/C + IrO2 catalyzed ZAB (65%). For the long-term cycling test, as shown in Figure , the FeNi-NC@MWCNT catalyzed ZAB demonstrates a narrower charge/discharge voltage gap and negligible voltage drop after 300 h cycling, suggesting its superior durability which outperforms most of the recently reported SAC/DAC catalyzed ZABs (SI, Table ). In contrast, substantial charge-discharge voltage drop was observed in the reference ZAB with Pt/C+IrO2 mixture after 75 h. Based on the above results, the FeNi-NC@MWCNT is a promising and robust alternative to precious metal-based catalysts for both primary and rechargeable Zn-air batteries.