In-situ self-templating construction of FeNi/N co-doped 3D porous carbon from bimetallic ions-coordinated porous organic polymer for rechargeable zinc-air batteries

Herein, an in-situ self-templating approach is applied to construct FeNi/N co-doped 3D porous carbon from bimetallic (Fe/Ni) ions-coordinated porous organic polymer (denoted as OPOP-FeNi). The OPOP-FeNi precursor is synthesized by polycondensation of sodium benzene-1,3,5-tris(olate) with cyanuric chloride followed by co-ordination with Fe3+/Ni2+, in which the in-situ generated NaCl can serve as template for the construction of 3D -interconnected hierarchical porous architecture during the pyrolysis process. The as-constructed FeNi/N-C-800 can offer high electrocatalytic activities toward ORR/OER with a high half-wave potential of 0.845 V (vs. RHE) in ORR and a low potential of 1.600 V (vs. RHE) at 10 mA cm-2 in OER. The outstanding ORR/OER activities render FeNi/N-C-800-based rechargeable zinc-air battery (RZAB) with long cycling life (1500 cycles/1000 h at 5.0 mA cm-2), much more stable than previous reports on RZABs. Moreover, DFT calculations and poisoning experiments have been conducted to unveil the outstanding bifunctional activity of FeNi/N-C-800 electrocatalyst.