Sacrificial template synthesis of hierarchical nickel hydroxidenitrate hollow colloidal particles for electrochemical energy storage

Synthesis of hollow colloidal particles with a well-defined structure in a single step is challenging and highly desired for numerous applications. We propose a simple and productive approach to synthesize hierarchical nickel hydroxidenitrate hollow colloidal particles (NiHNHCP) with tunable structure and property via a one-pot manner for the application in supercapacitor. In this approach, the formation of the NiHN shells and the dissolution of the melamine-formaldehyde (MF) template particles occur simultaneously and successively under a solvothermal condition with time. It is found that the nickel precursors can protonate the solvent, declining the pH and further causing the dissolution of the MF particles. Meanwhile, the nickel precursors transform into NiHN nanosheets that self-assemble into hierarchical shells exclusively at the surface of the MF particles. With the reactions proceeding, the NiHNHCP are yielded ultimately. These NiHNHCP are characterized with superior electrochemical performance, making them practically useful in the application of supercapacitor. (C) 2020 Elsevier Ltd. All rights reserved.