Investigation of the Na Storage Property of One-Dimensional CuSe Nanorods.

In this study, one-dimensional CuSe nanorods synthesized by a simple water evaporation-induced self-assembly approach are served as the anode material for Na-ion batteries for the first time. CuSe electrodes express outstanding electrochemical properties. The initial discharge capacity is 149.3 mA h g at a current density of 100 mA g, and the discharge capacity can remain at 106.2 mA h g after 400 cycles. Even at a high current density of 2000 mA g, the discharge capacity of the CuSe electrode still remains at 62.8 mA h g, showing excellent rate performance. Owing to the excellent electronic conductivity and one-dimensional structure of CuSe, the CuSe electrodes manifest fast Na ion diffusion rate. Moreover, detailed Na insertion/extraction mechanism is further investigated by ex situ measurements and theoretical calculations.