Fe1−xS@S-doped carbon core–shell heterostructured hollow spheres as highly reversible anode materials for sodium ion batteries
Iron sulfide (Fe1−xS) has been considered as a promising anode material for sodium ion batteries (SIBs) because of its high theoretical capacity. However, Fe1−xS suffers from large volume change and sulfur dissolution issues during the sodiation/desodiation process, which lead to a poor cycle performance. Here, heterostructured Fe1−xS@S-doped carbon (Fe1−xS@SC) hollow spheres (HSs) have been prepared as SIB anode material. The Fe1−xS@SC HSs show a high reversible capacity of 776.2 mA h g−1 at 0.2 A g−1 and 454.3 mA h g−1 at 1.0 A g−1 after 500 cycles. The constructed Fe1−xS/SC heterojunctions play a key role in alleviating the large volume variation and stabilizing the reaction products Fe0 and Na2S, thus enhancing the conversion reaction kinetics of Fe0 and Na2S and ultimately resulting in a highly reversible conversion reaction. This work provides a possibility to solve the reversibility issue of conversion-type anode materials.
- This article is part of the themed collection: 2019 Journal of Materials Chemistry A HOT Papers