Formation of Hierarchical Cobalt Hydroxychloride Nanostructures with Enhanced Performance for Lithium‐Ion Batteries

Abstract Layered metal hydroxide salts have attracted considerable attention in various applications due to their superior photoelectric, physical, and chemical properties. Here, a simple in situ growth hydrothermal approach is reported to prepare hierarchical cobalt hydrochloride (Co 2 (OH) 3 Cl) microspheres composed of octahedron‐like subunits. Based on the multiple functional triethanolamine and time‐dependent morphology evolution, the formation of the unique sphere structures can be elucidated by a hierarchical self‐assembly of anisotropic nanoparticles. When used as lithium ion battery (LIB) anodes, this Co 2 (OH) 3 Cl microsphere shows very large reversible specific capacity (1196 mA h g –1 at 0.2 A g –1 ), excellent rate capability (720.4 mA h g −1 at 4.0 A g −1 ), and long‐life stability (802 mA h g –1 with 81.1% retention after 500 cycle tests at 4.0 A g –1 ). The excellent electrochemical performance is attributed to the improvement of electrical conductivity and fast ionic diffusion in the electrode by improving the microarchitecture and functionally introducing Cl – .