High efficacy of substrate dimensionality control in optimizing the specific capacitance and phase stability of hybridized nanostructures

Abstract

The hybridization with conductive nanostructures has attracted intense research interest because of its high efficiency in the exploration of efficient energy-functional materials. In this study, we reported a high efficacy of substrate dimensionality control in optimizing the specific capacitance and phase stability of hybridized nanostructures. Employing defective holey TiN nanostructures as substrates was found to enhance the interfacial interactions with a hybridized layered double hydroxide (LDH). A comparative investigation of two-dimensional TiN-LDH nanohybrids with zero-dimensional/one-dimensional TiN-LDH homologs demonstrated that hybridization with holey two-dimensional TiN nanosheets led to a much greater specific capacitance of 2127 F g−1, which is one of the best performances among LDH-based electrodes ever-reported. In situ Raman analysis during electrochemical cycling clearly demonstrated that holey nanosheet morphology of TiN substrate is quite crucial in promoting the phase transition of hybridized Ni-Fe-LDH to NiOOH/FeOOH with the maximization of cation redox activities. These advantages of atomically thin holey TiN nanosheets could be ascribed to intimate electronic coupling at the bilateral interfaces of the two-dimensional LDH nanosheets, in addition to optimized porosity and improved mass transport.