Core-shell FeS₂@NSC grown on graphene for high performance lithium-ion storage

FeS2 is considered a promising anode candidate for LIBs (lithium-ion batteries) due to its low cost and high theoretical capacity. However, the large volume expansion and low conductivity of FeS2 limit its further applications. In this work, a novel FeS2 -based materials with two-carbon encapsulated structure has been designed to solve the above problems. This unique structure is constructed of spindle-shaped FeS2 nanoparticles embedded in N/S co-doped carbon shell and covered by three-dimensional sulfur-doped graphene (FeS2@NSC/SG). The FeS2@NSC/SG composite shows excellent lithium storage performance benefiting from the unique twocarbon encapsulated structure. FeS2@NSC/SG electrode delivers a reversible capacity of 944.6 mAh-g(-1) after 120 cycles at 0.1 Ag-1 when it is used as anode for LIBs. Even at 5 Ag-1, the capacity of FeS2@NSC/SG electrode remains 270.8 mAh-g(-1) after 500 cycles. The excellent rate performance of FeS2@NSC/SG electrode is attributed to the electrochemical behavior dominated by the capacitive behavior and this strategy will provide new ideas for potential electrode materials.