Novel and multifunctional inorganic mixing salt-templated 2D ultrathin Fe/Co-N/S-carbon nanosheets as effectively bifunctional electrocatalysts for Zn-air batteries

[Display omitted] •2D ultrathin Fe/Co-N/S-Cs were ingeniously fabricated by a novel and multifunctional inorganic mixing salt-template route.•Fe/Co-N/S-Cs with ultrathin thickness exhibit ultrahigh SSA (1589 m2 g−1) and TPV (0.92 cm3 g−1).•Fe/Co-N/S-Cs catalysts show high E1/2 = 0.832 V for ORR and extremely low overpotential of 285 mV at 10 mA cm−2 for OER.•Zn-air batteries with Fe/Co-N/S-Cs catalysts exhibit high power density and excellent stability. 2D bimetallic and bi-nonmetallic codoping porous carbon nanosheets with more accessible surface area and active sites are especially potential electrocatalyst for oxygen reduction and oxygen evolution reaction (ORR and OER) of Zn-air batteries but the synthesis of this material has been rarely reported owing to excessively harsh requirements. Here, bimetallic (Fe/Co) and bi-nonmetallic (N/S) codoping porous carbon nanosheets (Fe/Co-N/S-Cs) with uniform and ultrathin thickness of about 4.63 nm were first synthesized by a novel and multifunctional inorganic mixing salt-template (FeCl3 and CoSO4). Fe/Co-N/S-Cs exhibit ultrahigh specific surface area (SSA: 1589 m2 g−1), total pore volume (TPV: 0.92 cm3 g−1), homogeneous distribution of heteroatom dopants, as well as an appropriate amount of carbon defects. Fe/Co-N/S-Cs show high half-wave potential (E1/2 = 0.832 V) for ORR and extremely low overpotential of 285 mV at 10 mA cm−2 for OER, exceeding most reported electrocatalysts. Furthermore, assembled Zn-air batteries employing Fe/Co-N/S-Cs as cathode catalyst exhibit high power density (102.63 mW cm−2) and excellent stability. This investigation sheds light on syntheses of superior but cheap electrocatalysts for developing next energy-related storage technology.