Facile Synthesis of Rod-like Cu Se and Insight into its Improved Lithium-Storage Property.

A rod-like Cu Se is synthesized by a facile water evaporation process. The electrochemical reaction mechanism is investigated by ex situ X-ray diffraction (XRD). By adopting an ether-based electrolyte instead of a carbonate-based electrolyte, the electrochemical performance of Cu Se electrodes improved significantly. The Cu Se electrodes exhibit outstanding cycle performance: after 1000 cycles, 160 mA h g can be maintained with a retention of 80.3 %. At current densities of 100, 200, 500, and 1000 mA g , the capacity of a Cu Se/Li battery was 208, 202, 200, and 198 mA h g , respectively, showing excellent rate capability. The 4-probe conductivity measurements along with electrochemical impendence spectroscopy (EIS) and cyclic voltammetry (CV) tests illustrate that the Cu Se electrodes display high specific conductivity and impressive lithium-ion diffusion rate, which makes the Cu Se a promising anode material for lithium-ion batteries.