A Faster Lithium Ion Diffusion Pathway Constructed by Uniform Distribution of Sulfur Using Simple One Step Spray Drying Method

Abstract The uniform distribution of sulfur in the cathode materials is a key factor for enhancing sulfur utilization in Li−S batteries. However, the widely used melt−diffusion method is suffering from nonuniform distribution of sulfur, agglomeration of cathode materials and uncontrollable sulfur contents, especially in large scale preparation process. In this work, a simple one step spray drying method to prepare sulfur uniformly distributed cathode materials in kilogram−scale is provided. A faster Li+ diffusion pathway is constructed benefit by the uniform distribution of sulfur in spay drying derived samples, which results in high Li+ diffusion coefficient, high sulfur utilization and good electrochemical performance. Density function theory calculation has proved that adding of TiN nano powder increased the polysulfides adsorption capacity and enhanced the cycling stability. The spray drying derived S/T/CNTs−70 cathode materials revealed an initial discharge capacity of 1465 mA h g−1 at 0.1 C. The capacity decayed to 1200 mA h g−1 at 0.3 C and maintained at 842 mA h g−1 after 200 cycles. Furthermore, a Li−S pouch cell with a nominal capacity of 2 A h was fabricated using S/T/CNTs−70 as cathode. 31 paralleled light−emitting diodes (LEDs) are lighted sustainably by the Li−S pouch cell, which affirmed the practical value of the one step spray drying method.