Facile Synthesis of Ni/Co (Hydr)oxides with Nanosheet Structure for High Performance Supercapacitors

摘要

In this article, the novel kind of binary metal oxides, Ni/Co (hydr)oxides, with nanosheet structurehave been successfully established via a facile hydrothermal self-assembled process with ammoniasolution as the reaction reagent. The as-prepared samples with peculiar morphologies andcharacteristics are easily realized by just controlling the calcination temperatures. The composition,morphology, and microstructure of the products were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM)and X-ray photoelectron spectroscopy (XPS). The thermogravimetric analysis (TGA) revealed thedecomposition details of the precursor. Electrochemical measurements show that the sample calcinedat 250C has the optimized capacitive performance, demonstrated by cyclic voltammetry andgalvanostatic charge-discharge cycling techniques. The Ni/Co hydroxide nanosheets as electrode-1 -1 -1 materials for supercapacitor exhibit high specific capacitance of 1427 F g at 1 A g , and 1270 F g at-1 10 A g , indicating an excellent rate capability. Also, the superior cyclic stability with the capacitance-1 retention of 92.3% is achieved even over 3000 cycles at a high current density of 10 A g . Theimproved capacity and cycling stability makes it promising electrode material for offering an effectiveway to achieve high supercapacitor performance.