Bimetallic hydroxyl fluoride with high‐rate lithium storage performance: Co0.6Zn0.4(OH)F material

Summary In this study, we synthesized a bimetal hydroxyl fluoride, Co0.6Zn0.4(OH)F, with an overlapping nanoneedle structure using a simple hydrothermal method. The synthesized Co0.6Zn0.4(OH)F was used as a new electrode material to study its electrochemical performance. Because of the synergy between Co and Zn and the high ionicity of fluorides, the Co0.6Zn0.4(OH)F electrode exhibited a discharge capacity of 1355.5 mAh g−1 during the first charging and discharging cycle. After 400 cycles at a current density of 2 A g−1, the Co0.6Zn0.4(OH)F electrode showed an excellent specific capacity of 756 mAh g−1. The Co0.6Zn0.4(OH)F electrode also exhibited an excellent capacitance contribution rate, indicating good rate performance. In addition, the hydroxyl and oxygen vacancies in the electrode material promoted the lithium/dilithium reactions. Therefore, Co0.6Zn0.4(OH)F is an excellent lithium storage material with high rate; thus, it has a certain potential application value in the future. The samples form overlapping nano needle structure, which increases the specific surface area and active center, so that the electrode material has high specific capacity at high current density.