Interfacial Coupling SnSe2/SnSe Heterostructures as Long Cyclic Anodes of Lithium‐Ion Battery

Abstract Tin selenide (SnSe 2 ) is considered a promising anode of the lithium‐ion battery because of its tunable interlayer space, abundant active sites, and high theoretical capacity. However, the low electronic conductivity and large volume variation during the charging/discharging processes inevitably result in inadequate specific capacity and inferior cyclic stability. Herein, a high‐throughput wet chemical method to synthesize SnSe 2 /SnSe heterostructures is designed and used as anodes of lithium‐ion batteries. The hierarchical nanoflower morphology of such heterostructures buffers the volume expansion, while the built‐in electric field and metallic feature increase the charge transport capability. As expected, the superb specific capacity (≈911.4 mAh g −1 at 0.1 A g −1 ), high‐rate performance, and outstanding cyclic stability are obtained in the lithium‐ion batteries composed of SnSe 2 /SnSe anodes. More intriguingly, a reversible specific capacity (≈374.7 mAh g −1 at 2.5 A g −1 ) is maintained after 1000 cycles. The internal lithium storage mechanism is clarified by density functional theory (DFT) calculations and in situ characterizations. This work hereby provides a new paradigm for enhancing lithium‐ion battery performances by constructing heterostructures.