Continuous Compositing Process of Sulfur/Conductive‐Additive Composite Particles for All‐Solid‐State Lithium Sulfur Batteries

Abstract

All‐solid‐state lithium‐sulfur (ASS‐Li/S) batteries have recently attracted considerable attention owing to their high energy density and safety. To produce the cathode of an ASS‐Li/S battery, sulfur (the cathode active material) must be combined with a conductive additive (electron conductor) because of the electronic insulating property of sulfur. Therefore, a compositing process of sulfur and conductive additives is necessary to produce ASS‐Li/S batteries. However, existing compositing methods are neither scalable nor productive. Herein, for the first time, a hot‐melt kneading process, as a scalable and productive compositing process, to produce composite particles of sulfur and a conductive additive for ASS‐Li/S batteries is employed. The composite particles prepared from the hot‐melt kneading process show larger particle sizes, less fine conductive additive particles, and better flowability than the simple mixture. The obtained composite particles have a matrix‐type structure, in which conductive additive particles exist even inside the sulfur particles. Concerning the electrochemical performance, compositing sulfur and a conductive additive using the hot‐melt kneading process improves the electrochemical performance because of the matrix‐type structure of the composite particles. Moreover, by estimating the productivity of the process, the study demonstrates that the hot‐melt kneading process has a significantly better productivity compared with conventional compositing processes.

Keywords

• composite cathodes
• hot-melt kneading
• lithium-sulfur batteries
• solid-state batteries