Hierarchical NiAl LDH nanotubes constructed via atomic layer deposition assisted method for high performance supercapacitors

Abstract

Layered double hydroxides (LDHs) have attracted wide attentions in supercapacitor fields owing to their versatile physical and chemical properties. In this work, hierarchical NiAl LDH nanotubes consisting of ultrathin nanosheets were synthesized by integrating an atomic layer deposition (ALD) technique with a simple hydrothermal treatment. The present NiAl LDH has the unique structural features that offer large ion-accessible surface area and efficient ion transport pathways. The developed NiAl LDH nanotubes exhibit an excellent electrochemical performance including high specific capacitance, excellent rate performance and outstanding cycling stability as a battery-type electrode for supercapacitors. Thereinto, the 10NiAl-LDH-based electrodes can provide an initial specific capacitance of 2123.7Fg−1 at a current density of 0.5Ag−1, and 91.9% of the initial capacitance is retained after 10000 cycles at a current density of 5Ag−1. We believe that the excellent electrochemical performance for 10NiAl-LDH should mainly be ascribed to the appropriate Ni2+/Al3+ ratio, diameter of nanotubes and thickness of nanosheets determined by thickness of ALD Al2O3, and the detailed mechanism is discussed.