Strain-Regulated Pt-NiO@Ni Sub-Micron Particles Achieving Bifunctional Electrocatalysis for Zinc-Air Battery.

Highly active bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) have always been the key factors to affect the performance of zinc-air batteries. However, integrating the independent reaction sites of ORR and OER in a catalyst remains a major challenge. Herein, a collaborative strategy based on defect induction and doping is proposed to prepare the strain-regulated Pt-NiO@Ni sub-micron particles (Pt-NiO@Ni SP). Benefiting from the synergistic effect of tensile strain and Pt-doped, the metallic Ni-based sub-micron particles with tensile strain as the catalyst carriers can effectively optimize the electronic distribution of atomic structures in Pt and NiO on the surface of particles, leading to reduce the energy barrier of intermediates for ORR and OER. Consequently, the Pt-NiO@Ni SP exhibits outstanding bifunctional catalytic activity with the ΔE index of 0.65 V under a low Pt loading, outperforming that of the benchmark Pt/C+IrO2 catalysts (0.76 V). Impressively, the Pt-NiO@Ni SP-based liquid zinc-air battery develops a high open-circuit potential (1.47 V), excellent energy density (188.2 mW cm-2 ), and favorable cyclic charge-discharge cycling durability (200 h at 20 mA cm-2 ). This work provides an innovative avenue for the rational construction of highly active bifunctional electrocatalysts for practical applications.