Standing and Lying Ni(OH)2 Nanosheets on Multilayer Graphene for High-Performance Supercapacitors

Abstract

For conventional synthesis of Ni(OH)2/graphene hybrids, oxygen-containing functional groups should be firstly introduced on graphene to serve as active sites for the anchoring of Ni(OH)2. In this work, a method for growing Ni(OH)2 nanosheets on multilayer graphene (MLG) with molecular connection is developed which does not need any pre-activation treatments. Moreover, Ni(OH)2 nanosheets can be controlled to stand or lie on the surface of MLG. The prepared hybrids were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The growth processes are suggested according to their morphologies at different growth stages. The enhanced electrochemical performances as supercapacitor electrode materials were confirmed by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques. Ni(OH)2 nanosheets standing and lying on MLG show specific capacities of 204.4 mAh g−1 and 131.7 mAh g−1, respectively, at 1 A g−1 based on the total mass of the hybrids and 81.5% and 92.8% capacity retention at a high current density of 10 A g−1, respectively. Hybrid supercapacitors with as-prepared hybrids as cathodes and activated carbon as anode were fabricated and tested.

Uniform Fe2O3Nanospheres Anchored on Multilayer Graphene as Anode Materials for High‐Rate Ni−Fe Batteries

“…75–1621), meaning that MLG still maintains an integral layer structure of graphite. More characterization of MLG with SEM, TEM, XPS, AFM in our previous publications [32–35] showed that MLG consists of about 10 graphitic layers with a very low oxidation degree. No other peaks are found for all samples, indicating the high purity of these composites.…”

“…The crystalline phases of UL-Fe 2 O 3 /MLG samples were analyzed by XRD. As shown in Figure 1, the peaks at 24 [32][33][34][35] showed that MLG consists of about 10 graphitic layers with a very low oxidation degree. No other peaks are found for all samples, indicating the high purity of these composites.…”

“…Ni(OH) 2 /MLG was prepared according to our published paper [33] . Briefly, 170 mg of NiCl 2 ⋅ 6H 2 O and 70 mg of urea were added into the MLG suspension (20 mg of MLG in 8 mL of DMF and 2 mL of H 2 O) and mixed homogeneously with magnetic stir.…”

“…Ni(OH) 2 /MLG was prepared according to our published paper. [33] Briefly, 170 mg of NiCl 2 • 6H 2 O and 70 mg of urea were added into the MLG suspension (20 mg of MLG in 8 mL of DMF and 2 mL of H 2 O) and mixed homogeneously with magnetic stir. Then, the mixture was poured into a 30 mL Teflon-lined steel autoclave, sealed and kept at 150 °C for 2-hour reaction.…”

Cucurbit[6]uril supported β-Ni(OH)2 nanoparticles as a heterogeneous catalyst for the synthesis of quinazolines via acceptorless dehydrogenative coupling of alcohols with nitriles

“…38,39 Nickel nanoparticles and their oxides have emerged as efficient catalysts in hydrogenolysis, 40,41 dehydrogenation, 42 condensation reactions, 43,44 reduction reactions, 45 and C-C bond formation. [46][47][48] A perusal of the literature reveals that Ni(OH) 2 NPs have been used in the field of electrocatalysis, [49][50][51][52][53] photocatalysis, [54][55][56][57] supercapacitors, [58][59][60][61] and heterogeneous catalysis, [62][63][64] yet Ni(OH) 2 NPs remain relatively less explored in the arena of catalysis. Unsupported Ni(OH) 2 NPs exhibit a tendency to agglomerate.…”