Carbon-coated ZnS as a high-performance ORR/OER bifunctional cathode catalyst for zinc-air batteries

Abstract

The commercial application of zinc-air batteries (ZABs) is hindered by the high cost and scarcity of precious metal catalysts. In this paper, we prepared high-performance ORR/OER bifunctional catalysts with a carbon-coated ZnS spherical structure (ZnS@C) through a hydrothermal method followed by a carbonization process. Characterized by their unique spherical coated pore structure, exhibit impressive electrocatalytic activity. Specifically, ZnS@C-2, produced by a secondary carbonization process demonstrates an ORR half-wave potential of 0.82 V (relative to RHE) and an OER overpotential of 377 mV at 10 mA cm−2. When employed in a ZAB, it achieves a maximum power density of 120.4 mW cm−2, a specific capacity of 836 mAh gZn−1, and maintains cycle stabilization for up to 165 h at 10 mA cm−2. The research results demonstrate that the unique carbon-coated internal porous structure not only significantly enhances the stability of the catalyst but also increases the number of active sites, thereby providing more abundant activation energy for the catalytic reaction and facilitating its efficient progress. This underscores the catalyst's excellent ORR and OER properties, suggesting promising practical application potential.