Triphilic organochalcogen compounds for high-capacity and stable solid-state lithium–sulfur batteries

Abstract

The triple-phase interface among the active material, conductive host, and solid-state electrolyte is critical for achieving high-performance solid-state sulfur cathodes. However, solid–solid contact often creates unfavorable interfaces with low ion/electron transport efficiency and limited durability, leading to reduced discharge capacity and compromised cycling stability. To overcome this challenge, we introduce a novel hybrid inorganic–organic cathode design that uses sulfur and organochalcogen compounds (i.e., phenyl disulfide/diselenide) as active materials. These organochalcogen compounds, with a low melting point of 60 °C, exhibit a good affinity for sulfur, carbon, and solid-state electrolytes in their molten state. This triphilic feature enables uniform integration among cathode components with efficient and robust interfaces. Consequently, introducing a small amount of organochalcogen compounds (2 wt% of cathode weight) enhances discharge capacity (>1000 mA h g⁻¹), rate capability, and cycling stability (>400 cycles) in full cells.