Spinning Disk Reactor Technique for the Synthesis of Nanometric Sulfur TiO₂Core–Shell Powder for Lithium Batteries

Abstract

Sulfur/lithium battery performances are strictly related to the morphology and nanostructure of sulfur particles. In this work, a comparison of the morphological characteristics and electrochemical properties of electrodes based on colloidal sulfur (CS) obtained by means of traditional chemical precipitation from aqueous solution and via spinning disk reactor (SDR) has been performed. In particular, through the SDR technique and by using different fluid dynamic conditions, it was possible to obtain monodisperse and nanometricsulfurparticles with higher electrochemical performances when used as the cathodic active material in lithium batteries. Moreover, a method to produce core−shell nanoparticles with sulfur and titanium dioxide, starting from a colloidal sulfur (S8) solution and produced by SDR, has been performed, obtaining good electrochemical results. In particular, the nanometric sulfur powder produced by the SDR technique showed a capacity higher than CS after 100 cycles, even if the capacity decreased rapidly in both cases. Instead, considering the core−shell S−TiO2 material, the nanostructured electrode allowed a wide use of active material and a reduced capacity decay during cycling. Specifically, the material showed an initial capacity of 1395 mAh/g, i.e., representing 83% of the theoretical value, which decreased during operation up to 450 mAh/g after about 30 cycles. Then, the material capacity remained unchanged and no substantial loss of capacity was recorded up to 100th cycle.

Keywords

• Lithium-sulfur battery
• spinning disk reactor technique
• S–TiO₂ core–shell structure
• sulfur nanoparticles
• cathode materials