One-Step In Situ Self-Assembly of Cypress Leaf-Like Cu(OH)2 Nanostructure/Graphene Nanosheets Composite with Excellent Cycling Stability for Supercapacitors

Abstract

Transition metal hydroxides and graphene composite holds great promise to be the next generation of high performance electrode material for energy storage applications. Here we fabricate the cypress leaf-like Cu(OH) 2 nanostructure/graphene nanosheets composite through one-step in situ synthesis process, employed as a new type of electrode material for high efficiency electrochemical energy storage in supercapacitors. A solution-based two-electrode system is applied to synthesize Cu(OH) 2 /graphene hybrid nanostructure, where anodic graphene nanosheets firmly anchor cathodic Cu(OH) 2 nanostructure due to the electrostatic interaction. The in situ self-assembly of Cu(OH) 2 /graphene ensures good structural robustness and the cypress leaf-like Cu(OH) 2 nanostructure prompt to form the open and porous morphology. The hybrid structure would facilitate charge transport and effectively mitigate the volume changes during long-term charging/discharging cycles. As a consequence, the Cu(OH) 2 /graphene composite exhibits the highest capacitance of 317 mF/cm 2 at the current density of 1 mA/cm 2 and superior cyclic stability with no capacitance decay over 20,000 cycles and remarkable rate capability at increased current densities.

High electromagnetic interference shielding effectiveness in MgO composites reinforced by aligned graphene platelets

“…Therefore, the electron transfer at the MgO/graphene interface may occur from graphene to MgO. 38,39 As illustrated in Figure 4C MgO exhibit good contacts, consistent with the date shown in Figure 3F TEM images of the microstructure of the graphene/MgO composite bulk sample are shown in Figure 5A. The grain size of MgO is approximately 200 nm.…”

“…Based on this result, the monolayer graphene is in good contact with MgO. Therefore, the electron transfer at the MgO/graphene interface may occur from graphene to MgO 38,39 . As illustrated in Figure 4C, except for Mg‐O (531.2 eV), the C = O and C‐O vibrations in the O 1 s peaks are located at 529.8 and 532.2 eV, respectively.…”

One-Step Electrochemically Prepared Graphene/Polyaniline Conductive Filter Membrane for Permeation Enhancement by Fouling Mitigation

“…According to the literature, − using an aqueous inorganic salt solution as the electrolyte, by the electrochemical method, highly conductive Gr nanosheets could be obtained from the anode peeling graphite. The mixture of ammonium sulfate solution and ammonia had been frequently used as the electrolyte in the one-step electrochemical researches. ,, In this paper, the electrolyte was prepared by mixing 200 mL of ammonium sulfate solution (0.1 mol L –1 ) with 10 mL of ammonia at room temperature; a graphite foil (4 × 5 cm 2 ) was used as the anode and the same-sized PANI membrane was used as the cathode. The graphite foil and the PANI membrane were placed in the electrolyte vertically, and the distance between the cathode and the anode was adjusted to 1 cm.…”

“…Recent studies have shown that Gr nanosheets can be prepared by the anodic electrochemical exfoliation approach. − Subsequently, a direct one-step electrochemical method to obtain Gr composites is also provided, and the method is simple in process and safe in operation. ,, According to Ma et al, using graphite foil and Ni foam as the anode and the cathode, respectively, by the two-electrode system liquid-phase electrochemical exfoliation method, Gr was synchronously stripped and assembled on a three-dimensional (3D) Ni­(OH) 2 network synchronously; then, the acquired materials were made into supercapacitors. Other applications of the anode Gr include serving as a noble-metal catalyst support, in making transparent and conductive continuous Gr circuits, and so on.…”

Influence of Stirring Time on the Electrochemical Properties of NiCo2S4 Hexagonal Plates and NiCo−OH Nanoparticles as High‐Performance Pseudocapacitor Electrode Materials

“…The non‐rectangular shapes of the CV curves of NCS hexagonal plates and NiCo−OH NPs at each scan rate within the potential window of 0.0 V to 0.6 V designate reversible redox behavior of the electrodes. Meanwhile, the oxidation and reduction peaks shift towards more positive and negative potentials, due to high electron hopping resistance or limited ion diffusion time . Likewise, a pair of prominent redox peaks was observed in each curve, confirming the presence of Co 2+ /Co 3+ and Ni 2+ /Ni 3+ redox reactions with OH − ions in the KOH electrolyte.…”