Self-assembled N-doped MoS2/carbon spheres by naturally occurring acid-catalyzed reaction for improved sodium-ion batteries

Abstract

Molybdenum disulfide (MoS2) has been considered a promising anode material for sodium ion batteries (SIBs) because of its relatively high theoretical capacity and 2D-layered structure. However, the intrinsically low electronic conductivity of MoS2 and its severe volume change during battery operation lead to poor rate capability and cyclability. In this study, nitrogen self-doped MoS 2 /carbon spheres (denoted as N-MoS2/C) were easily synthesized through a facile naturally occurring acid-catalyzed method, which takes advantage of the selfdoping effect of thioacetamide as a sulfur as well as nitrogen co-source and the self-polymerization property of furfural as a carbon source. The enlarged interlayer and defect-containing N-MoS2/C provides not only sufficient active sites to diffuse electrons and sodium ions but also a buffer structure, which can accommodate volume change during sodiation/desodiation. The unique structure of N-MoS2/C demonstrates remarkable electrochemical performances, such as high rate capability (charge capacity of 387.9 mAh g(-1) at 10 C-rate), superior cyclability (capacity retention of 78% over 200 cycles at 0.2 C-rate), and high-rate cycling (capacity retention of over 96% even after 100 cycles at 1, 2, and 5 C-rate).