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

Abstract

Pyrite iron disulfide (FeS 2 ) has aroused wide attention owing to its high theoretical capacity, making it a promising anode material for sodium-ion batteries (SIBs). Unfortunately, the poor electrical conductivity, large volume variation, and sluggish ion-migration kinetics lead to inferior rate capability and cycle stability, thus limiting its practical application. Herein, utilizing Prussian blue analogues (PBAs) as precursors, hollow heterostructured CoS 2 /FeS 2 nanoparticles confined in N, S dual-doped carbon nanofibers (denoted as H-CoS 2 /FeS 2 @CNFs) are successfully developed via facile electrospinning, carbonization, and gas sulfurization processes. The effective combination of a unique hollow heterostructure and highly conductive N, S dual-doped CNFs can accelerate electron transport and ion diffusion kinetics, avoid aggregation of active materials, and obtain enhanced structural stability. As expected, the optimal H-CoS 2 /FeS 2 @CNFs-2 hybrid composite delivers a high reversible capacity of 542.6 mA h g −1 after 150 cycles at 0.5 A g −1 and outstanding cycling stability with a capacity of 323.7 mA h g −1 over 1500 cycles at 5.0 A g −1 , showing the excellent sodium storage capability for SIBs. The rational design offers inspiration for fabricating high-performance bimetallic sulfides as anodes of SIBs through spatial confinement and a heterogeneous interface engineering strategy.

Achieving High-Rate and Stable Sodium-Ion Storage by Constructing Okra-Like NiS2/FeS2@Multichannel Carbon Nanofibers

“…Moreover, the XRD patterns of these samples are depicted in Figure S5. All the diffraction peaks of NiS 2 /FeS 2 particles matched well to bulk NiS 2 and FeS 2 phases, certifying the formation of heterostructured NiS 2 /FeS 2 , while the diffraction peaks of NiS 2 /FeS 2 @MCNFs and NiS 2 /FeS 2 @CNFs are quite similar to those of NiS 2 /FeS 2 except for the obviously decreased peak intensities, possibly attributing to the signal shielding of NiS 2 /FeS 2 particles by the shell carbon nanofibers . The detailed electrochemical properties of these samples shall be analyzed and discussed in the following context.…”

Introduction of SnS2 to Regulate the Ferrous Disulfide Phase Evolution for the Construction of Triphasic Heterostructures Enabling Kinetically Accelerated and Durable Sodium Storage

“…These excellent electrochemical performances of FFS‐TH are superior to the reported iron/tin sulfides‐based composite electrodes (Figure 4f). [ 17,18,21,37,44–54 ]…”