Layered MoSi2N4 as Electrode Material of Zn–Air Battery

Metal–air batteries have an outstanding advantage of combining high‐energy‐density metal anodes with active air cathodes. The advanced properties of layered materials can be utilized to improve the internal reaction rate and charge storage of metal–air batteries. Layered MoSi 2 N 4 is a newly synthesized MAX phase (where M is transition metal, A is Al or Si, and X is C, N, or both). This work investigates the possibility of MoSi 2 N 4 , a layered MAX phase, as both the cathode and anode of Zn–air batteries. The mechanism of Zn storage is revealed. As a Zn storage material, phase transition from state I to state III occurs with increasing Zn loading in MoSi 2 N 4 . The maximum theoretical capacity of Zn‐loaded MoSi 2 N 4 is 257 mAh g −1 . On MoSi 2 N 4 surface as the cathode, the two‐electron mechanism of O 2 reduction to ZnO 2 is more efficient than general sluggish four‐electron aqueous O 2 redox reactions. The work reveals the possibility of MAX phases as the electrodes of Zn–air batteries and the mechanism of Zn storage in 2D MAX layered materials.