Nanosized FeS₂ Particles Caged in the Hollow Carbon Shell as a Robust Polysulfide Adsorbent and Redox Mediator

Abstract

As one of the most promising candidates for next-generation energy storage technology, lithium–sulfur (Li–S) battery has been attracting increasing attention due to its high theoretical specific capacity (1675 mA h g–1), natural abundance, and environmental friendliness. However, the notorious shuttle effect caused by the soluble polysulfides as well as the sluggish redox kinetics significantly hinders the practical application. Herein, sulfiphilic iron disulfide (FeS2) nanoparticles caged in the hollow carbon shell have been facilely fabricated as the sulfur host (FeS2@C-S) for Li–S batteries. The deposited amorphous carbon cage with hollow space can provide efficient pathways for electrons, facilitate electrolyte penetration, and effectively accommodate the volume change during the repeated charge/discharge process. In addition, polar FeS2 nanoparticles have strong chemical interaction on the polysulfides and can promote the redox conversion of polysulfides as an electrocatalyst. Visible adsorption and electrochemical analysis have been conducted to confirm the static polysulfide trapping capability and dynamic polysulfide conversion reversibility. Synergistically, the FeS2@C-S cathode with a sulfur loading of ∼1.5 mg cm–2 exhibits high cycle stability with a reversible capacity of ca. 800 mA h g–1 after 200 cycles at a current density of 0.2 C and excellent rate performance. Even at the current density of 5 C, a capacity of ca. 400 mA h g–1 can still be achieved after 400 cycles. This work provides a feasible approach to provide both physical and chemical protection against polysulfides resulting from the synergistic effects of multifunctional units during the sulfur cathode development.

Sulfophobic and Vacancy Design Enables Self‐Cleaning Electrodes for Efficient Desulfurization and Concurrent Hydrogen Evolution with Low Energy Consumption

“…The closer redox states of sulfur species in the lattice of catalysts and solutions may facilitate the desulfurization (Figure 1b). Although anion redox processes recently receive increasing attention in designing the OER catalyst and high‐energy batteries, [ 28–30 ] it remains unexplored how compounds having partly oxidized diatomic anions affect the catalysis and desorption of sulfur species.…”

Silica-Assisted Controlled Engineering of Nitrogen-Doped Carbon Cages with Bulges for High-Performance Supercapacitors

“…The hard-template method is one of the most popular approaches in preparing carbon cages because it can successfully copy the morphology of the template. , This method can be used in a wide range of materials and size of operations and can be scaled up. MgO has become a widely used hard template for preparing carbon cages because of its flaky morphology and wide range of sources .…”

Enhancing Catalytic Conversion of Polysulfides by Hollow Bimetallic Oxide-Based Heterostructure Nanocages for Lithium-Sulfur Batteries

“…To address these issues, especially to suppress the shuttling of lithium polysulfides (LiPSs), abundant methods − have been made, which can be classified as physical confinement, chemical adsorption, and catalysis. − Various composite materials − have been applied as sulfur hosts, such as carbon materials, − polymers, , metal oxides, , metal nitrides, metal sulfides, , metal phosphides, , etc. Among them, different carbon materials ,− are the most widely researched because of their superior electroconductibility and high surface areas.…”