Encapsulated CoxSy nanoparticles decorated S, N-doped mesoporous carbon as effective bifunctional oxygen electrocatalyst in rechargeable Zn-air battery

Exploiting effective non-noble metal electrocatalysts is imperative and challenging for advanced Zn-air batteries (ZABs). This paper reports a type of S,N co-doped mesoporous carbon hybrids decorated with encapsulated cobalt sulfide nanoparticles (CoxSy/SNC) by a facile method. The hybrid pyrolyzed at 800 degrees C (CoxSy/SNC-800) shows optimal microstructure, and possesses abundant active sites. Additionally, the synergistic effect between the Co(x)S(y )nanoparticles and graphitic-carbon matrices can effectively improve the electrocatalytic activities. Therefore, CoxSy/SNC-800 exhibits a high half-wave potential of 0.80 V towards oxygen reduction, low overpotential of 350 mV at 10 mA cm(-2) towards oxygen evolution, and excellent electrocatalytic stability. The bifunctional oxygen activity is super to the commercial catalysts and comparable with the recent reported electrocatalysts. Moreover, a ZAB with the CoxSy/SNC-800 as air-electrode catalyst displays a peak power density of 136 mW cm(-2), low charge/discharge voltage gap and outstanding cycling stability. Undoubtedly, this finding provides a simple strategy for preparing low-cost bifunctional catalyst in advanced energy conversion and storage devices. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study introduces a type of S,N co-doped mesoporous carbon hybrids decorated with encapsulated cobalt sulfide nanoparticles, which exhibits excellent electrocatalytic activities due to the synergistic effect between the Co(x)S(y) nanoparticles and graphitic-carbon matrices. The hybrid shows superior performance in both oxygen reduction and oxygen evolution, providing a potential option for air-electrode catalysts in advanced Zn-air batteries.