Synergistically catalytic enhanced of Zn-N/Co-N dual active sites as highly efficient and durable bifunctional electrocatalyst for rechargeable zinc-air battery

The theoretical energy density, stability and cost of Zn-air batteries (ZAB) are far inferior to the most advanced lithium-ion batteries due to the irreversibility of zinc electrodes and sluggish electrocatalytic performance of oxygen reduction (ORR) and oxygen evolution (OER) processes. Herein, we designed a simple strategy to fabricate a quaternary Zn-Co-N-S co-doped tubular carbon (0.3-Zn-Co-N/S-C) via direct pyrolysis of various mixtures of precursors. The high porosity of 3D nanostructure not only provides better mass transfer but also offers a large number of active sites thereof superior ORR and OER performances. As a result, the rechargeable ZAB fabricated using optimized 0.3-Zn-Co-N/S-C as cathode exhibited a higher open-circuit voltage, stable discharge rate, and better reversibility, even exceeding the state-of-the-art Pt/C catalyst in alkaline solution. The catalytic mechanism indicates that the synergistic effect of Co metal nanoparticles, Co-N/Zn-N active sites, and the high-yield of N/S-doped tubular carbon dominate the outstanding catalytic performance.

Automated summary

A high-porosity Zn-Co-N-S co-doped tubular carbon was designed to enhance the efficiency of the oxygen reduction reaction, leading to superior performance of ZAB batteries surpassing Pt/C catalyst. The outstanding catalytic performance is mainly attributed to the synergistic effect of Co metal nanoparticles, Co-N/Zn-N active sites, and the high-yield of N/S-doped tubular carbon.