Cu 2 SnSe 3 /CNTs Composite as a Promising Anode Material for Sodium-ion Batteries

Metal selenides as anode materials for sodium-ion batteries have attracted considerable attention owing to their high theoretical specific capacities and variable composition and structures. However, the achievement of long cycle life and superior rate performance is challenging for these selenide materials due to the volume variation upon cycling. Herein, a composite composed of a new binary-metal selenide[Cu 2 SnSe 3 (CSS)] and carbon nanotubes(CNTs) was constructed via a hydrothermal process followed by calcination at 600 °C. Benefited from the unique structure of binary-metal selenide and the conductive network of CNTs, the Cu 2 SnSe 3 /carbon nanotubes(CSS/CNT) composite exhibits excellent electrochemical performance when used as an anode material for sodium-ion batteries. A reversible specific capacity of 399 mA·h/g can be maintained at a current density of 100 mA/g even after 100 cycles. This work provides a promising strategy for rational design of binary-metal selenides upon delicate crystal phase control as electrode materials.