In situ synthesized SnSe nanorods in a SnOx@CNF membrane toward high-performance freestanding and binder-free lithium-ion batteries

Abstract

The poor reversibility of the first conversion reaction (SnO₂ + 4Li⁺ + 4e⁻ → Sn + 2Li₂O) and the inferior electrical conductivity of the resulting Li₂O make tin oxides not make full use of their lithium storage performance. In this study, various amounts of SnSe nanorods were in situ incorporated into SnO_x@CNFs via electrospinning and thermal treatment processes. Binder-free SnSe/SnO_x@CNFs exhibit a greatly enhanced lithium-ion storage performance due to their higher electrical conductivity, faster Li-ion diffusivity, and better reversible ability. The optimal SnSe/SnO_x@CNFs exhibited a higher initial coulombic efficiency (86.5%) and better reversible capacity (740.7 mA h g⁻¹ at 200 mA g⁻¹ after 70 cycles) than pristine SnO_x@CNFs (68.1%, 552 mA h g⁻¹ at 200 mA g⁻¹ after 70 cycles). Moreover, the high capacity of the SnSe/SnO_x@CNF electrode can be maintained as high as 345 mA h g⁻¹ at 1 A g⁻¹ over 1000 cycles, demonstrating its robust long-term stability. This work provides new insights for designing high-performance tin-based anode materials for lithium-ion batteries.