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

In this work, nonstoichiometric Cu2–xSe fabricated by a facile water evaporation process is used as high-performance Al-ion battery cathode materials. Cu2–xSe 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 Cu2–xSe electrodes is also revealed by the GITT, which is attributed to the ultrahigh electronic conductivity of the Cu2–xSe material. Most importantly, an extensive research is dedicated to investigating the detailed intercalation and de-intercalation of relatively large chloroaluminate anions into the cubic Cu2–xSe, which is conducive to better understand the reaction mechanism of the Al/Cu2–xSe battery.