Realizing Interfacial Electronic Interaction within ZnS Quantum Dots/N-rGO Heterostructures for Efficient Li-CO2 Batteries

With high theoretical energy density, rechargeable metal-gas batteries (e.g., Li-CO2 battery) are considered as one of the most promising energy storage devices. However, their practical applications are hindered by the sluggish reaction kinetics and discharge product accumulation during battery cycling. Currently, the solutions focus on exploration of new catalysts while the thorough understanding of their underlying mechanisms is often ignored. Herein, the interfacial electronic interaction within rationally designed catalysts, ZnS quantum dots/nitrogen-doped reduced graphene oxide (ZnS QDs/N-rGO) heterostructures, and their effects on transformation and deposition of discharge products in the Li-CO2 battery are revealed. In this work, the interfacial interaction can both enhance the catalytic activities of ZnS QDs/N-rGO heterostructures and induce the nucleation of discharge products to form a homogeneous Li2CO3/C film with excellent electronic transmission and high electrochemical activities. When the batteries cycle within a cutoff specific capacity of 1000 mAh g(-1) at a current density of 400 mA g(-1), the cycling performance of the Li-CO2 battery using a ZnS QDs/N-rGO cathode is over 3 and 9 times than those coupled with a ZnS nanosheets (NST)/N-rGO cathode and a N-rGO cathode, respectively. This work provides comprehensive understandings on designing catalysts for Li-CO2 batteries as well as other rechargeable metal-gas batteries.