Graphene-supported Fe/Ni single atoms and FeNi alloy nanoparticles as bifunctional oxygen electrocatalysts for rechargeable zinc-air batteries
The development of inexpensive and high-performance bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of crucial significance for rechargeable metal-air batteries , but remains challenging. Herein, we report an ingenious bifunctional oxygen electrocatalyst integrating ZIF-derived carbon-anchored Fe/Ni single atoms, FeNi alloy nanoparticles , and graphene support (denoted as Fe/Ni-NC||FeNi@G). Synergizing highly active Fe single atoms for the ORR and highly efficient FeNi alloy nanoparticles for the OER, the as-constructed Fe/Ni-NC||FeNi@G catalyst exhibits outstanding bifunctionality; the potential gap between the OER potential at 10 mA cm –2 and the ORR half-wave potential is only 0.618 V, outperforming the benchmark Pt/C + Ir/C catalyst and most transition metal-based bifunctional catalysts reported in the literature. More importantly, the Fe/Ni-NC||FeNi@G-driven zinc-air battery (ZAB) delivers a maximum power density of ∼200 mW cm –2 , a specific capacity of 876 mAh g –1 , and excellent cycling stability with negligible voltage decay up to 500 hours (3000 cycles). This work provides an effective approach to designing highly efficient non-noble metal multifunctional catalysts for practical applications in rechargeable metal-air batteries.
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