Synthesis of interlayer expanded MoS2 by sulfurization of MoO3 with enhanced sodium-ion storage

Abstract

MoS2, high theoretical specific capacity (670 mAh g−1) and unique physical and chemical properties, is widely used as the anode of sodium-ion batteries (SIBs). However, the original MoS2, with its inferior inherent conductivity and serious volume variation during charge and discharge, often exhibits low actual capacity and poor rate performance. In this work, MoS2 nanoflower was synthesized by sulfurization of molybdenum trioxide (MoS2-MT), which expanded interlayer distance without mixing with other materials. The expanded interlayer distance (about 0.68 nm) reduced the diffusion barrier of Na+. The larger specific surface area increased the contact area between the electrode material and the electrolyte, which provided more active sites for the insertion/extraction of Na+. As anode of SIBs, MoS2-MT achieved a high specific capacity of 535.3 mAh g−1 at 0.1 A g−1, and reserved 410 mAh g−1 at 1 A g−1 after 100 cycles with a capacity retention rate of 85.4%. At the same time, MoS2-MT also exhibited considerable rate performance that reserved 313.5 mAh g−1 at 5.0 A g−1.