FeOOH Nanorod-Assisted Carbon Cloth Sandwich Cathodes for Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries are acknowledged as one of the most promising secondary batteries due to their high theoretical specific capacity and high energy density. Nevertheless, Li–S batteries are particularly susceptible to the lithium polysulfide “shuttle effect” and sluggish kinetic transformations under high sulfur loading. In this work, a sandwich-structured self-supporting electrode (FeCC/S-FeCC) is fabricated to alleviate the aforementioned issues. FeOOH nanorods were vertically and uniformly deposited on the surface of carbon cloth (CC) through hydrothermal synthesis, resulting in a self-supporting composite material (FeCC) that serves both as the sulfur carrier and as the interlayer. Additionally, it ingeniously utilizes physical and chemical effects to effectively trap polysulfides and facilitate the acceleration of redox reactions. Cyclic voltammetry and electrochemical impedance spectroscopy testing reveal that Li+ diffusion in the FeCC/S-FeCC cathode is speedy, and the charge transfer resistance is relatively low, facilitating electron/ion transport (DLi+ = 1.10 × 10–6 cm2 s–1). The meticulously designed cathode with high sulfur loading of 7.9 mg cm–2 achieves an initial discharge specific capacity of 820.1 mAh g–1 at 0.1 C, and it retains 86% after 100 cycles. This work employed a structural engineering approach to design a sandwich cathode with high sulfur loading, effectively enhancing its performance and offering valuable insights for the structural design of sulfur cathodes.