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

Abstract

Tin selenide (SnSe2) 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 SnSe2/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 SnSe2/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.