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

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.

Automated summary

Composite particles of sulfur and a conductive additive prepared by a hot-melt kneading process exhibit improved electrochemical performance due to the matrix-type structure of the composite particles. Additionally, the study demonstrates that the hot-melt kneading process has significantly better productivity compared to conventional compositing processes.