Interface engineering Ni/Ni12P5@CNx Mott-Schottky heterojunction tailoring electrocatalytic pathways for zinc-air battery.

ABSTRACT

Due to the poor bifunctional electrocatalytic performances of electrocatalysts in zinc-air battery, herein, we first synthesized Ni/Ni12P5@CNx Mott-Schottky heterojunction to ameliorate the high-cost and instability of precious metals. We modulated the different contents of Ni and Ni12P5 in the Ni/Ni12P5@CNx Mott-Schottky heterojunction, and found that 0.6 Ni/Ni12P5@CNx has outstanding electrocatalytic performances, with half-wave potential of 0.83 V, and OER potential of 1.49 V at 10 mA cm-2. Also, the ΔE value is only 0.66 V. Moreover, 0.6 Ni/Ni12P5@CNx is assembled into ZAB, which has a high power density of 181 mW cm-2 and a high specific capacity of 710 mAh g-1. This indicates it has a good cycle stability. The density functional theory (DFT) calculations reveal that electrons spontaneously flow from Ni to Ni12P5 through the formed buffer layer in the Ni/Ni12P5@CNx Mott-Schottky heterojunction. The Schottky barrier formed modulates the electrocatalytic pathway to have good bifunctional electrocatalytic activity for ORR and OER.