A binder-free dry coating process for high sulfur loading cathodes of Li-S batteries: A proof-of-concept

A promising candidate for next-generation energy storage is the lithium-sulfur battery (LSB) due to its high capacity and low-cost active material (sulfur). However, the practical application of LSBs is challenged by poor cycling life and low sulfur loading. Herein, a proof-of-concept for manufacturing high load electrodes with a low-cost dry (solvent-free) coating process with a reduced carbon footprint is introduced and investigated. This process is often based on fluoropolymer-based binder additives with health and environmental concerns. Therefore, this study presents the concept of a binder-free dry coating process using sulfur/carbon black (S/CB) composites derived from a straight-forward dispersive mixing process. The electrodes are fabricated by a hot-pressing process, taking advantage of sulfur melting into a carbon matrix. To determine the process-structure-property relationships of the resulting powders, electrodes and cells, a novel structure determination by thermogravimetric analysis was used. Mixing time turns out to be an important factor, which has a significant effect on the electrode performance. The cells assembled with electrodes (similar to 4.5 mgS cm(-2)) made from optimized powder mixtures showed a high specific capacity of about 800 mAh g(S)(-1), and a relatively improved C-rate capability.

Automated summary

This paper introduces a solvent-free low-cost dry coating process for manufacturing high load electrodes and investigates its impact on the performance of lithium-sulfur batteries. The electrodes fabricated through hot-pressing process exhibit high specific capacity and improved rate capability.