CoS₂ and FeS₂ Nanoparticles Embedded in Carbon Polyhedrons for Lithium–Sulfur Batteries

Abstract

CoS 2 and FeS 2 nanoparticles with mesoporous structures embedded in carbon polyhedrons are prepared by reasonable design of materials (CoS 2 -FeS 2 -NC), which are used as a modified cathode material. This composite material can limit the shuttling of polysulfides and catalyze and adsorb polysulfides. Further, electrochemical properties of Li−S batteries are enhanced. Li−S batteries using S/CoS 2 -FeS 2 -NC electrodes have the best cycle and rate performance. The S/CoS 2 -FeS 2 -NC cathode's initial discharge capacity at 0.2C is 938.9 mAh g −1 , while its reversible capacity remains 394.8 mAh g −1 after 200 cycles, with a 0.28% decline on average. S/CoS 2 -NC and bare sulfur cathodes have maximal discharging capacities of 82.3 and 63.8% of S/CoS 2 -FeS 2 -NC cathodes at 0.2C. The initial discharge capacity of S/CoS 2 -FeS 2 -NC at 0.5C is 795.6 mAh g −1 , and the capacity of 354.4 mAh g −1 is maintained after 200 cycles. So, S/CoS 2 -FeS 2 -NC has excellent electrochemical properties.

Prussian Blue Analogue Derived CoS2/FeS2 Confined in N, S Dual-Doped Carbon Nanofibers for Sodium Storage

“…It is noteworthy that the isostructural CoS 2 has lattice constants very similar to those of FeS 2 , making it quite difficult to distinguish them from the obtained XRD data. 38,39 Further insights into the morphology and internal structure of the H-CoS 2 /FeS 2 @CNFs-2 hybrid composite were further gained by TEM and HRTEM measurements. The representative TEM images as depicted in Figure 2A,B show a well retained interconnected fibrous structure of the H-CoS 2 / FeS 2 @CNFs-2 hybrid composite after the high-temperature calcination process.…”

“…42-1340), as supported by the amplified XRD pattern in Figure S1. It is noteworthy that the isostructural CoS 2 has lattice constants very similar to those of FeS 2 , making it quite difficult to distinguish them from the obtained XRD data. , …”

Prussian Blue Analogues Derived Heterostructured CoS2/FeS2 Particles Anchored on Carbon Nanosheets as Anodes for Boosted Sodium Storage Properties

“…42-1340). [28,29] Besides, the broad diffraction peak at around 26.1°arising from the amorphous carbon is retained from the intermediate product of CoÀ Fe PBA/C. The XRD result clearly demonstrates the successful conversion of CoÀ Fe PBA during the carbonization and sulfurization processes, and the existence of mixed phases of CoS 2 and FeS 2 within the hybrid composite.…”

Fe7Se8 Nanostructures with Carbon Skeleton and Core–Shell Design As Anodes for Lithium Ion Batteries

“…Transition metal dichalcogenides (TMDs), such as CoS, MoS 2 , FeS 2 , and Cu 2 S, have garnered significant interest owing to their high theoretical capacity, small volume expansion, and good electrical conductivity. − Comparatively, transition metal selenides (TMSs) exhibit higher electrical conductivity and better electrochemical properties due to the weaker metal–selenium bonds than TMDs but have attracted less attention. − TMSs suffer from large volume expansion after Li insertion, leading to destruction of the electrode structure, and thus a sharp capacity decrease during the cycling process. − Therefore, the structure of the TMS electrode must be well-protected to enable a stable cycling process. Based on previous reports, forming porous nanostructures and coupling carbon materials are common strategies to solve these problems. − For example, in order to address the issue of pulverization resulting from large volume expansion of CoP during the cycle, Li’s group synthesized a peapod-like CoP@C complex, the unique 0D-in-1D porous nanostructure provides sufficient space for volume expansion, and accessible nanopore channels for Li + transport, obtaining a specific capacity of 490 mAh g –1 at a current of 1.0 A g –1 . For improving the material conductivity and shortening the electron transport distance, Liu’s group fabricated sulfides/C composites with a porous nanostructure and robust carbon skeleton, achieving a reversible capacity of 791 mAh g –1 after 100 cycles at 0.2 A g –1 .…”