Elastic Sandwich‐Type rGO–VS2/S Composites with High Tap Density: Structural and Chemical Cooperativity Enabling Lithium–Sulfur Batteries with High Energy Density

Abstract

AbstractDriven by increasing demand for high‐energy‐density batteries for consumer electronics and electric vehicles, substantial progress is achieved in the development of long‐life lithium–sulfur (Li–S) batteries. Less attention is given to Li–S batteries with high volume energy density, which is crucial for applications in compact space. Here, a series of elastic sandwich‐structured cathode materials consisting of alternating VS2‐attached reduced graphene oxide (rGO) sheets and active sulfur layers are reported. Due to the high polarity and conductivity of VS2, a small amount of VS2 can suppress the shuttle effect of polysulfides and improve the redox kinetics of sulfur species in the whole sulfur layer. Sandwich‐structured rGO–VS2/S composites exhibit significantly improved electrochemical performance, with high discharge capacities, low polarization, and excellent cycling stability compared with their bare rGO/S counterparts. Impressively, the tap density of rGO–VS2/S with 89 wt% sulfur loading is 1.84 g cm−3, which is almost three times higher than that of rGO/S with the same sulfur content (0.63 g cm−3), and the volumetric specific capacity of the whole cell is as high as 1182.1 mA h cm−3, comparable with the state‐of‐the‐art reported for energy storage devices, demonstrating the potential for application of these composites in long‐life and high‐energy‐density Li–S batteries.