Atomic Ni and Cu co-anchored 3D nanoporous graphene as an efficient oxygen reduction electrocatalyst for zinc-air batteries

Highly active, cost-effective and durable electrocatalysts for the oxygen reduction reaction (ORR) are critically important for renewable energy conversion and storage. Here we report a 3D bicontinuous nitrogen doped nanoporous graphene electrocatalyst co-anchoring with atomically dispersed nickel and copper atoms ((Ni,Cu)-NG) as a highly active single-atom ORR catalyst, fabricated by the combination of chemical vapor deposition and high temperature gas transportation. The resultant (Ni,Cu)-NG exhibits an exceptional ORR activity in alkaline electrolytes, comparable to the Pt-based benchmarks, from the synergistic effect of the CuN x and NiN x complexes. Endowed with high catalytic activity and outstanding durability under harsh electrochemical environments, rechargeable zinc-air batteries using (Ni,Cu)-NG as the cathodes show excellent energy efficiency (voltage gap of 0.74 V), large power density (150.6 mW cm −2 at 250 mA cm −2 ) and high cycling stability (>500 discharge-charge cycles at 10 mA cm −2 ). This study may pave an efficient avenue for designing highly durable single-atom ORR catalysts for metal-air batteries. Important progress is reported in the development of dual single-atom transition metal co-anchored catalysts, CuN x and NiN x moieties anchored on 3D nanoporous graphene, with superior ORR activities and durability for zinc-air batteries.