Novel hierarchically branched CoC2O4@CoO/Co composite arrays with superior lithium storage performance

Hierarchically branched array architectures have received tremendous research attention for the application in energy conversion and storage owing to their unique microstructures. Herein, novel in-situ formed hierarchically branched CoC2O4@CoO/Co composite arrays are successfully designed and prepared via a facile self-corrosion process and subsequent calcination treatment. The resultant CoC2O4@CoO/Co composite materials have a novel hierarchically branched array microstructure, with secondary CoC2O4 nanoneedles in-situ grown on the surface of primary cores. As the binder-free anodes for lithium ion batteries (LIBs), the hierarchically branched CoC2O4@CoO/Co composite arrays exhibit remarkable electrochemical lithium storage properties, including high reversible capacity, excellent cycling performance, and superior rate capability. Further kinetic analyses reveal that capacitance and diffusion-controlled mechanisms are responsible for their high electrochemical lithium storage, and the pseudocapacitive behavior can contribute extra capacity. This structural design concept may open an avenue for the construction of hierarchically branched high-performance materials for application in energy conversion and storage devices.