Highly Oxidized Graphene Anchored Ni(OH)2 Nanoflakes as Pseudocapacitor Materials for Ultrahigh Loading Electrode with High Areal Specific Capacitance

摘要

The contact between Ni(OH)2 and graphene oxide (GO) determines the specific capacitance, high-rate performance, and stability of Ni(OH)2-GO composites when they were used as capacitive materials with high/ultrahigh material loading. To improve this contact, the exfoliated GO from Hummers' method is oxidized twice for anchoring Ni(OH)2 nanoflakes. The X-ray photoelectron spectroscopy (XPS) results reveal that the further oxidation process increases the carbonyl (C—O) groups and oxygen content on the GO surface. The Ni(OH)2-GO composites were obtained through a simple hydrothermal process. Morphology and microstructure characterizations indicate that the further oxidation of GO improves the affinity of Ni(OH)2 and GO via the increased surface groups on the GO. Due to the high conductivity and suitable structure, the Ni(OH)2 anchored on the treated GO (Ni(OH)2/TGO) exhibits good capacitive performance and high areal specific capacitance.