Facile preparation of carbon wrapped copper telluride nanowires as high performance anodes for sodium and lithium ion batteries.

Uniform carbon wrapped copper telluride nanowires were successfully prepared by using an in situ conversion reaction. The length of these nanowires is up to several micrometers and the width is around 30-40 nm. The unique one dimensional structure and the presence of conformal carbon coating of copper telluride greatly accommodate the large volumetric changes during cycling, significantly increase the electrical conductivity and reduce charge transfer resistance. The copper telluride nanowires show promising performance in a lithium ion battery with a discharge capacity of 130.2 mA h g at a high current density of 6.0 A g (26.74 C) and a stable cycling performance of 673.3 mA h g during the 60th cycle at 100 mA g. When evaluated as anode material for a sodium ion battery, the copper telluride nanowires deliver a reversible capacity of 68.1 mA h g at 1.0 A g (∼4.46 C) and have a high capacity retention of 177.5 mA h g during the 500th cycle at 100 mA g.