Bimetallic hydroxyl fluoride with high‐rate lithium storage performance: Co _{0. 6} Zn _{0 .4} ( OH )F material

Abstract

In this study, we synthesized a bimetal hydroxyl fluoride, Co 0.6 Zn 0.4 (OH)F, with an overlapping nanoneedle structure using a simple hydrothermal method. The synthesized Co 0.6 Zn 0.4 (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 Co 0.6 Zn 0.4 (OH)F electrode exhibited a discharge capacity of 1355.5 mAh g À1 during the first charging and discharging cycle. After 400 cycles at a current density of 2 A g À1 , the Co 0.6 Zn 0.4 (OH)F electrode showed an excellent specific capacity of 756 mAh g À1 . The Co 0.6 Zn 0.4 (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, Co 0.6 Zn 0.4 (OH)F is an excellent lithium storage material with high rate; thus, it has a certain potential application value in the future.bimetallic fluoride, Co 0.6 Zn 0.4 (OH)F, electrochemical characteristics, LIBs, nanoneedle | INTRODUCTIONPresently, various portable and fixed electronic devices and electric vehicles use lithium-ion batteries (LIBs) as a power source. [1][2][3] Currently, common mechanisms, such as anodic material lithiation, 4 alloying, 5 and conversion reactions, 6 have been developed, and several battery systems, particularly carbon, 7 silicon, 8 and lithium-based systems 9 have been used. The electrochemical