Influence of Primary Particle Morphology and Hydrophilicity of Carbon Matrix on Electrode Coating Quality and Performance of Practical High‐Energy‐Density Li–S Batteries

• Published in: Advanced materials interfaces Vol. 11; no. 7
• Main Authors: Li, Shanglin, Chen, Zhaoyue, Yamamoto, Kentaro, Watanabe, Toshiki, Uchimoto, Yoshiharu, Mori, Yuki, Inoue, Gen, Ohuchi, Kazuya, Inagaki, Satoshi, Ueno, Kazuhide, Dokko, Kaoru, Watanabe, Masayoshi
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 01.03.2024; Wiley-VCH
• Subjects: Carbon; Cathodes; composite sulfur cathode; Electrodes; Electrolytic cells; high‐energy‐density battery; Lithium sulfur batteries; lithium–sulfur battery; mesoporous carbon; Morphology; pouch cell; Storage batteries; Wettability
• ISSN: 2196-7350; 2196-7350
• DOI: 10.1002/admi.202300864

Li–S batteries have attracted attention as the next‐generation secondary batteries. While substantial progress is made in understanding Li–S chemistry at a fundamental level, only a limited number of studies are dedicated to achieving high energy density at the practical pouch cell level. The challenge lies in attaining high‐energy‐density Li–S batteries under harsh conditions, which involve a minimal amount of electrolyte and a relatively high areal S‐loading cathode. This discrepancy creates a substantial gap between fundamental material research and comprehensive cell‐level investigations. In this study, it is investigated how the morphology and properties of two carbon materials, namely Ketjen black (KB) and mesoporous carbon nano‐dendrites (MCND), influence the composite cathode architecture and determine the performance of Li–S batteries. Unlike KB, MCND allows for a higher sulfur‐loading cathode without evident cracks in the composite cathode. This achievement can be attributed to the high porosity, excellent wettability, and high conductivity exhibited during an identical electrode preparation procedure. Furthermore, large‐format Li–S pouch cells incorporating MCND/S cathodes are successfully fabricated. These cells demonstrate an energy density surpassing 250 Wh kg−1 and an initial discharge capacity of 3.7 Ah under challenging conditions (S‐loading > 5 mg cm−2 and E/S < 3.5 µL mg−1). The carbon host for the sulfur cathode significantly influences the quality of electrode coatings and the performance of practical high‐energy‐density Li–S batteries. Mesoporous carbon nano‐dendrites (MCND), with dendritic primary particle morphology and hydrophilicity, enable crack‐free, porous, high wettability, and high conductivity cathode coatings. The MCND‐based cathode exhibits superior Li–S battery performance under high sulfur loading and lean electrolyte conditions.