Space-confined synthesis of CoNi nanoalloy in N-doped porous carbon frameworks as efficient oxygen reduction catalyst for neutral and alkaline aluminum-air batteries

Exploring efficient and stable non-precious metal electrocatalysts for oxygen reduction reaction in neutral and alkaline solutions is of great importance for metal-air batteries. Herein, an efficient and stable electrocatalyst with CoNi nanoalloy (10-20 nm) uniformly embedded in porous N-doped carbon framework (CoNi-NCF) for neutral and alkaline primary Al-air batteries is prepared and studied. The CoNi-NCF electrocatalyst shows superior ORR performance in terms of half-wave potential of 0.91 V in 0.1 M KOH solution and 0.64 V in 3.5 wt% NaCl solution, outperforming those of the commercial Pt/C catalyst. Supported by in situ electrochemical Raman spectra and density functional theory calculations, the rich dual active sites of CoNi nanoalloy and porous N-doped carbon contributes to the outstanding ORR performance. Impressively, when employed as a cathode catalyst in both aqueous and solid flexible Al-air batteries, the CoNi-NCF-based Al-air batteries show the highest discharge performance, long-time durability and high flexibility, demonstrating the promising potential for practical application.