3D Graphene Nanosheets Crosslinked Core–Shell FeS₂@N, S Co-Doped Porous Carbon for Improved Lithium/Sodium Storage Performance

Transition metal sulfides (TMS) hold great promise as anode materials for Li⁺/Na⁺ storage. However, their practical application still faces several challenges, such as inadequate electrical conductivity, substantial volume changes and a propensity for agglomeration. To tackle these challenges, a 3D composite structure composed of graphene nanosheets crosslinked core−shell FeS₂@N, S co−doped porous carbon (FeS₂@NSC/GNs) is created by combining self−template polymerization with the graphene encapsulation technique. Systematic characterization and analysis demonstrate the effectiveness of the self−template polymerization strategy in generating a porous core−shell structure, which facilitates the uniform dispersion and optimal contact of the FeS₂ core within the carbon shell. Concurrently, the integration of graphene, alongside the porous carbon shell, introduces a sophisticated dual−protection mechanism against volume expansion and undesirable FeS₂ aggregation. Furthermore, the resulting 3D architecture enables efficient electron/ion transport and provides abundant sites for Li⁺/Na⁺ storage. Leveraging these inherent benefits, the FeS₂@NSC/GNs composite exhibits significantly improved lithium/sodium storage performance in comparison to the counterparts. Evidently, our proposed approach offers valuable guidance for the construction of advanced anodes for lithium/sodium−ion batteries.