One-Dimensional Cu2–xSe Nanorods as the Cathode Material for High-Performance Aluminum-Ion Battery

In this work, nonstoichiometric Cu_{2- x}Se fabricated by a facile water evaporation process is used as high-performance Al-ion battery cathode materials. Cu_{2- x}Se electrodes show high reversible capacity and excellent cycling stability, even at a high current density of 200 mA g^-1, the specific charge capacity in the initial cycle is 241 mA h g^-1 and maintains 100 mA h g^-1 after 100 cycles with a Coulombic efficiency of 96.1%, showing good capacity retention. The prominent kinetics of Cu_{2- x}Se electrodes is also revealed by the GITT, which is attributed to the ultrahigh electronic conductivity of the Cu_{2- x}Se material. Most importantly, an extensive research is dedicated to investigating the detailed intercalation and de-intercalation of relatively large chloroaluminate anions into the cubic Cu_{2- x}Se, which is conducive to better understand the reaction mechanism of the Al/Cu_{2- x}Se battery.