Three-dimensional MoSx (1 < x < 2) nanosheets decorated graphene aerogel for lithium–oxygen batteries

Abstract

The electrochemical performance of lithium–oxygen (Li–O₂) batteries depends largely on the architecture and catalytic effectiveness of the oxygen cathode. Herein, in this study, a graphene aerogel decorated with MoS_x nanosheets (MoS_x/HRG) with a three-dimensional porous framework synthesized using a one-step hydrothermal reaction followed by freeze-drying is reported. The MoS_x/HRG aerogel possesses hierarchical mesopores and micropores, which could facilitate electrolyte impregnation and oxygen diffusion, and provide much more accommodation space for the reaction products. The lithium–oxygen batteries based on this MoS_x/HRG aerogel cathode show improved electrochemical performance, with a high initial discharge capacity up to 6678.4 mA h g⁻¹ at a current density of 0.05 mA cm⁻² and better cycling capability with a cut-off capacity of 500 mA h g⁻¹ at a current density of 0.1 mA cm⁻², compared with the lithium–oxygen batteries based on an HRG aerogel cathode. The enhanced performance is ascribed to the excellent catalytic activity of the MoS_x nanosheets and the unique three-dimensional porous architecture.