Co-doping-induced electronic reconfiguration of nanosized ZnS for facilitating oxygen reduction reaction in flexible aluminum–air batteries

The development of high-performance and cost-efficient catalysts holds great significance in facilitating oxygen reduction reaction (ORR), which is a pivotal process in next-generation energy storage devices, such as aluminum–air batteries. Transition metal sulfides have been proposed as promising non-noble metal ORR catalysts. However, achieving platinum (Pt)-comparable activity remains a challenge. Herein, a Co-doping-triggered electronic reconfiguration strategy is reported to tune the charge distribution and coordination state of ZnS nanoparticles anchored on N, S co-doped carbon (ZnS/NSC), thereby optimizing the intermediate adsorption kinetics and promoting ORR activity. The half-wave potential of 0.87 V as well as 100-h continuous durability are obtained by Co-doped ZnS/NSC in alkaline media. In addition, the solid-state aluminum–air battery is further assembled by using Co-doped ZnS/NSC as a cathode catalyst, achieving a maximum peak density of 100 mW·cm⁻² and discharge duration over 55 h. Density functional theory (DFT) calculations reveal that high electronegative Co-doping is beneficial for the construct of charge-transfer avenue and optimization of intermediate adsorption procedure. This study presents an efficient approach for preparing metal sulfides with high catalytic activity toward ORR in flexible metal–air batteries.