Reinforcing oxygen electrocatalytic activity via selective dual‐phase heterointerface engineering for rechargeable Zn–air batteries

Abstract

Abstract Dual‐phase heterointerface electrocatalysts (DPHE) constructed by oxygen reduction reaction (ORR)‐ and oxygen evolution reaction (OER)‐active elements exhibit excellent bifunctional activity and long‐term durability due to the abundant interface exposure and synergistic catalytic effect. Herein, low‐dimensional N‐doped graphene nanoribbons (N‐GNRs) coupling with ultrathin CoO nanocomposites (N‐GNRs/CoO) were controllably fabricated through a facile two‐step approach using synthesized Co(OH) 2 nanosheet as CoO precursor. Density functional theory (DFT) calculations and experimental characterizations prove that the formation of interface between N‐GNRs and CoO can induce local charge redistribution, contributing to the improvement of catalytic activity and stability. The optimal N‐GNRs/CoO DPHE possesses hierarchically porous architectures and presents outstanding bifunctional activities with a small potential gap of 0.729 V between the potential at 10 mA·cm −2 for OER and the halfwave potential for ORR, which outperforms Pt/C + IrO 2 and the majority of noble‐metal‐free bifunctional catalysts. Liquid‐ and solid‐state rechargeable Zn–air batteries assembled with N‐GNRs/CoO as the cathode also display high peak power density and fantastic cycle stability, superior to that of benchmark Pt/C + IrO 2 catalyst. It is anticipated to offer significant benefits toward high activity, stability and mechanical flexibility bifunctional oxygen electrocatalysts for rechargeable Zn–air batteries.