Porous core-shell structured nitrogen doped carbon coated Cu2SnSe4 nanorod for improved sodium ion battery anode

Binary metal selenides are promised as potential anodes for sodium storage by the reason of their desirable theoretical specific capacity and satisfied electronic conductivity. Nevertheless, the binary-metal selenides anodes normally undergo serious volume change and unsatisfactory cycle life. Herein, the porous core-shell structured nitrogen doped carbon coated Cu₂SnSe₄ nanorod (Cu₂SnSe₄@NC) was obtained by simple template method. The porous core-shell structure not only relieves volume effect of Cu₂SnSe₄@NC anode, but also promotes the electrolyte infiltration and facilitates Na⁺ migration. Moreover, the bimetallic composition and nitrogen doped carbon shell speed up electron transform and exhibit high-rate of Cu₂SnSe₄@NC anode. Benefiting from the above advantages, Cu₂SnSe₄@NC anode shows favorable electrochemical performance. The Cu₂SnSe₄@NC delivered a capacity of 263 mAh g⁻¹ at 7.0 A g⁻¹, and showed an excellent cyclic stability of 311 mAh g⁻¹ over 800 cycles at 2.0 A g⁻¹.