Cation-exchange induced high power electrochemical properties of core–shell Ni(OH)2@CoOOH

New applications such as hybrid electric vehicles and power backup require rechargeable batteries to combine high energy density with high charge and discharge rate capability. In this study, the core–shell Ni(OH)2@CoOOH composite is constructed via a simple cation-exchange route at moderate conditions. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), and inductively coupled plasma (ICP) are used to characterize the resulting Ni(OH)2@CoOOH composites. The Ni(OH)2@CoOOH electrode exhibits high power, higher capacity and longer life cycle when it is chosen as an positive electrode material for rechargeable alkaline MH-Ni battery. The enhanced electrochemical performance is attributed to the seamless combination of the CoOOH shell and the Ni(OH)2 core, avoiding the contact resistance between them at a large current density. It is believed that our methodology provides a simple and environment friendly route to a variety of core–shell materials with different composition and novel function.