Work

Multiscale design of an organosulfur cathode with superior cycling stability in ether electrolytes under practical conditions via selenium codoping

Year: 2026

Type: article

Abstract: The sulfurized polyacrylonitrile (SPAN) cathode, in which sulfur atoms are covalently bonded to the polyacrylonitrile (PAN) matrix, offers a promising strategy for avoiding the dissolution–precipitation mechanism of lithium polysulfides (LiPSs) in traditional Li–S batteries. However, the solid–solid conversion mechanism in SPAN cathodes is electrolyte-dependent, and the dissolution behavior of covalently bonded sulfur remains poorly understood. Elucidating this mechanism is important for understanding the sulfur reduction reaction (SRR) pathway in SPAN cathodes. Herein, we demonstrate that the LiPSs still dissolve from the SPAN matrix in ether-based electrolytes, which may promote SRR kinetics. We further show that the sulfur–PAN bonds at the cathode–electrolyte interfaces are vulnerable to being attacked by ether molecules. To address this issue, we introduce a selenization strategy to reinforce the bonding between sulfur species and the PAN matrix. The as-fabricated cathode enables rapid and stable lithium storage, achieving 77% of capacity retention over 200 cycles under practical conditions, including high mass loading of ~7 mg cm−2, low electrolyte-to-sulfur ratio of ~2.9 μL mg−1, and a limited negative-to-positive electrode capacity ratio of 1.5. This multiscale design strategy provides a promising approach for fabricating stable organosulfur cathodes for next-generation energy-storage systems.

Source: Energy Materials and Devices

DOI: 10.26599/emd.2026.9370108