Enhancing oxygen reduction of Fe-N-C active sites onto graphene via bismuth sacrifice for Zn-air batteries
Synthesizing low-cost electrocatalysts with rich metal-nitrogen-carbon active sites for the oxygen reduction reaction(ORR)is critical for developing high-performance Zn-air batteries.However,it is challenging for the pyrolysis cheap molecular precursors(such as melamine and iron salts)is chal-lenging because of the spontaneous aggregation of metal components and undesired byproducts during pyrolysis.Herein,we describe an approach to generate graphene-supported accessible Fe-N-C active sites by introducing a removable bismuth compound that efficiently inhibits the for-mation of iron-related particles and tubular carbon structures.The graphene-supported Fe(Bi)-N-C electrocatalyst exhibited high ORR activity under both alkaline(E1/2～0.916 V)and acidic(E1/2～0.784 V)conditions,along with excellent durability(15 mV degradation after 10 k cycles acceler-ated test).Using the catalytic material as the cathode,the Zn-air battery delivered a high power density of 201.4 mW cm-2 and a high stability over 1000 cycles.This investigation presents a prom-ising controlled pyrolysis solution for the scalable synthesis of low-cost,high-performance met-al-nitrogen-carbon-based catalytic materials.
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维普
