Engineering Pocket‐Like Graphene–Shell Encapsulated FeS₂: Inhibiting Polysulfides Shuttle Effect in Potassium‐Ion Batteries

Abstract

Resource‐rich FeS2 is a promising anode for potassium‐ion batteries (PIBs). However, polysulfides emerge due to FeS2 conversion during discharging, which dissolve into the ether‐based electrolyte and cause the continuous capacity degradation in PIBs. To address the polysulfides dissolution in PIBs, a graphene–shell‐encapsulated FeS2 is fabricated and embedded in N/S codoped 3D hollow carbon spheres. As a protective pocket, the graphene–shell can effectively accommodate polysulfides inside the core–shell, inhibiting the polysulfides shuttle effect to enhance cycle stability of electrode. The density functional theory (DFT) calculations demonstrate that graphene–shells have a strong adsorption capacity for polysulfides, and the interfacial interaction between KFeS2 and graphene–shell can boost the K ion mobility. As a result, the composite exhibits superior‐rate properties (524 and 224 mA h g−1 at 0.1 and 8 A g−1, respectively) and long‐term cycle stability. This work demonstrates the promotion and protective effect of the graphene–shell for the FeS2 to storage K from both experimental and computational perspectives. These research outputs can provide guidance for designing other metal‐based sulfide electrodes for PIBs.

MoS2 Nanosheets Anchored onto MIL-100(Fe)-Derived FeS2 as a Peroxymonosulfate Activator for Efficient Sulfamethoxazole Degradation: Insights into the Mechanism

“…The insertion structure was further confirmed by the TEM image of FeS 2 @MoS 2 -2 as shown in Figure h. As depicted in the high-resolution TEM (HRTEM) image of FeS 2 @MoS 2 -2 in Figure g, the lattice spacing of 0.62 nm was ascribed to the (002) crystal facet of 2H-phase MoS 2 and that of 0.27 nm corresponded to the (200) plane of FeS 2 . This agreed well with the XRD pattern results.…”

Spatially Confined “Edge‐to‐Edge” Strategy for Achieving Compact Na+/K+ Storage: Constructing Hetero‐Ni/Ni3S2 in Densified Carbons

“…The high‐resolution TEM images of Ni‐Ni 3 S 2 @SC in Figure 2e exhibit obvious lattice fringes with the interplanar spacing of about 0.20 and 0.28 nm, corresponding to the (111) plane of Ni and (110) plane of Ni 3 S 2 . [ 26–28 ] The closely connected lattice between Ni 3 S 2 and Ni demonstrates a well‐constructed heterointerface. Moreover, a well‐defined void in Ni 3 S 2 nanoparticles could be explicitly observed due to the Kirkendall effect (Figure 2f).…”

“…[ 33 ] Moreover, a small sharp protrusion located at a 2θ value of 26.3° corresponds to the (002) diffraction peak of carbon. [ 28 ] Raman spectrum was used to further identify the composition of the hybrid composite (Figure 3b). There are two typical peaks centered at ≈1347 and ≈1579 cm −1 belonging to the disordered D band and the graphitic G band, respectively.…”

NaCl Pinning Induced Ultrafine Sn Nanoparticles Anchored on Three-Dimensional Porous Carbon for Na Storage

“…It is clear that the potential increase during the discharge process and potential decrease of the Sn@C@3DC electrode during the charge process which were caused by the relaxation are significantly lower than that of the Sn@C electrode, suggesting faster Na + diffusion in the Sn@C@3DC electrode. The specific values of sodium diffusion coefficients are calculated based on eq : , where D indicates the Na + diffusion coefficient to be determined. L represents the Na + diffusion length (cm), corresponding to the thickness of the electrode.…”