Flexible SnSe2/N-doped porous carbon-fiber film as anode for high-energy-density and stable sodium-ion batteries

Tin selenide (SnSe2) is a prospective anode material for sodium ion batteries due to its large interlayer spacing and high theoretical capacity. Yet, there are few studies on the SnSe2-based flexible electrodes for Sodium-ion batteries (SIBs). In addition, the great volume expansion (≈420%) of SnSe2 during cycling, inevitably results in serious particles pulverization and aggregation, making it kinetic problems, and thus leading to limited rate capability and cycle stability in practical application. To overcome these problems, a SnSe2/nitrogen-doped porous carbon-fiber (SnSe2/NPC) flexible film with porous carbon-coated architecture and C–Se bond between the carbon-SnSe2 interface is designed and successfully prepared via electrospinning technology and high-temperature calcination and selenization. As anode material of SIBs, the SnSe2/NPC film electrode without conductive agent, binder and current collector, can result excellent rate capability and cycling stability. Furthermore, when the SnSe2/NPC film electrode are used in full cells, the full cell exhibits a high energy density of 119 Wh kg−1 and excellent cycling stability. This work provides an opportunity to exploit high-performance and long-life anodes for the practical applications of SIBs.