Synthesis of copper naphthalocyanine/graphene oxide composites as anode materials for lithium-ion batteries

Naphthalocyanine and its derivatives are new types of functional materials with wide application prospects. This paper discusses the synthesis of copper tetra tert-butyl-naphthalocyanine (CuNc) and analyses its molecular and electronic structure. Next, CuNc is combined with graphene oxide (GO) through π-π interaction and then pyrolyzed to form a CuNc/GO composite. A systematic investigation of the morphology, structure, composition and properties of CuNc/GO revealed that N-doped graphene is decorated with CuO particles. The electrochemical properties of CuNc/GO are compared with those of directly pyrolysed CuNc. The prepared CuNc/GO (1 : 1) electrode shows a large specific capacity (655.1 mA h g-1) after 100 cycles at 100 mA g-1. Its high capacity, enhanced cycling stability and strong rate performance are attributed to the synergetic effect of N-doped graphene and CuO particles. Besides expanding the use of naphthalocyanine compounds, this work presents a promising candidate material for lithium-ion battery anodes.

Applications of Ceramic/Graphene Composites and Hybrids

Research activity on ceramic/graphene composites and hybrids has increased dramatically in the last decade. In this review, we provide an overview of recent contributions involving ceramics, graphene, and graphene-related materials (GRM, i.e., graphene oxide, reduced graphene oxide, and graphene nanoplatelets) with a primary focus on applications. We have adopted a broad scope of the term ceramics, therefore including some applications of GRM with certain metal oxides and cement-based matrices in the review. Applications of ceramic/graphene hybrids and composites cover many different areas, in particular, energy production and storage (batteries, supercapacitors, solar and fuel cells), energy harvesting, sensors and biosensors, electromagnetic interference shielding, biomaterials, thermal management (heat dissipation and heat conduction functions), engineering components, catalysts, etc. A section on ceramic/GRM composites processed by additive manufacturing methods is included due to their industrial potential and waste reduction capability. All these applications of ceramic/graphene composites and hybrids are listed and mentioned in the present review, ending with the authors' outlook of those that seem most promising, based on the research efforts carried out in this field.

Novel single-step synthesis and shape transformation of Au/CuO micro/nanocomposites using plasma-liquid interaction

We report a novel single-step synthesis method of metal/metal oxide composites and transformation of the shape of the oxide material by Plasma-Liquid Interaction. Considering the potential applications of noble metal nanoparticle decorated copper oxide composites, we synthesize Au/CuO micro/nanocomposites by generating plasma between two copper electrodes inside a gold precursor (HAuCl₄) solution. Simultaneous synthesis of CuO and Au nanoparticles from the electrode material and from the precursor solution respectively is possible due to the interaction of energetic electrons and other active species formed in the plasma zone. Moreover, the process does not require any external stabilizing and reducing chemical agents. The method provides a remarkable tunability of the materials' physical and chemical properties by only controlling the precursor solution concentration. By controlling process parameters, the shape of CuO particles can be transformed from spindles to sheet-like and the size of Au nanoparticles can also be varied. It influences the particles' specific surface area and total pore volume. Plasmonic property of Au nanoparticles is also observed i.e. optical tunability can be achieved. The process is found to be effective for synthesis of desired nanomaterials having various energy storage and solar light-driven photocatalytic applications.

Graphene-Modified 3D Copper Foam Current Collector for Dendrite-Free Lithium Deposition

Lithium (Li) metal is regarded as the ideal anode for rechargeable Li-metal batteries such as Li-S and Li-air batteries. A series of problems caused by Li dendrites, such as low Coulombic efficiency (CE) and a short circuit, have limited the application of Li-metal batteries. In this study, a graphene-modified three-dimensional (3D) Copper (Cu) current collector is addressed to enable dendrite-free Li deposition. After Cu foam is immersed into graphene oxide (GO) suspension, a spontaneous reduction of GO, induced by Cu, generates reduced graphene oxide on a 3D Cu (rGO@Cu) substrate. The rGO@Cu foam not only provides large surface area to accommodate Li deposition for lowering the local effective current density, but also forms a rGO protective layer to effectively control the growth of Li dendrites. As current collector, the rGO@Cu foam shows superior properties than commercial Cu foam and planar Cu foil in terms of cycling stability and CE. The rGO@Cu foam delivers a CE as high as 98.5% for over 350 cycles at the current density of 1 mA cm⁻². Furthermore, the full cell using LiFePO₄ as cathode and Li metal as anode with rGO@Cu foam as current collector (LiFePO₄/rGO@Cu-Li) is assembled to prove the admirable capacities and indicates commercialization of Li-metal batteries.

Electrospun Carbon/Cu x O Nanocomposite material as Sustainable and High Performance Anode for Lithium-Ion Batteries

The increase in energy density of the next generation of battery materials to meet the new challenges of the electrical vehicles era calls for innovative and easily scalable materials with sustainable processes. An innovative Cu x O/C nanocomposite material, characterized by a highly conductive 3D-framework, with Cu x O/Cu-metal contiguous nanodomains is prepared by electrospinning. The electrode processing is made using a polyacrylic acid binder. The nanocomposite has been fully characterized and the electrochemical performance shows high specific capacity values over 450 galvanostatic cycles at 500 mAg-1 specific current with capacity retention values over 80 %. In addition, the composite shows remarkable high rate performance and highly stable interface, which has been studied by impedance spectroscopy.

Role of confining liquids on the properties of Cu@Cu2O nanoparticles synthesized by pulsed laser ablation and a correlative ablation study of the target surface

The effect of confining liquid on the properties of copper nanoparticles synthesized by pulsed laser ablation in two organic solvents, methanol and 2-propanol is investigated along with the effect of the laser irradiation time on the synthesized nanoparticles. To understand the role of confining liquids on the formation mechanism of the nanoparticles in different environments, the results obtained in the organic solvents are compared to those obtained in distilled water. The increase in the average size of the nanoparticles from 7-19 nm with the laser irradiation time from 15-60 minutes is accompanied by a shift in the plasmonic peak towards longer wavelength from 606-621 nm, respectively in methanol. In the case of nanoparticles synthesized in 2-propanol, the average size of the nanoparticles increases from 9-17 nm and there is a corresponding shift in the SPR peak from 581-601 nm, respectively. The increase in the size of the nanoparticles with the increase in irradiation time in the organic solvents is the reverse trend of that obtained for nanoparticles synthesized in distilled water. The range of the plasmonic peak positions is blue shifted for the nanoparticles synthesized in methanol and 2-propanol as compared to that of 626-641 nm for the nanoparticles synthesized in distilled water indicating the formation of insufficiently oxidized nanoparticles in organic solvents. Formation of core-shell spherical copper nanoparticles with carbon encapsulation in methanol and 2-propanol is another interesting observation. The origin of the dependence of properties of the synthesized nanoparticles on the ambient liquid lies in the way the laser beam interacts with the target surface in the ambient. A detailed ablation study on the laser produced crater in all the three liquids is carried out to understand the factors that affect the properties of the nanoparticles.

A facile coordination precipitation route to prepare porous CuO microspheres with excellent photo-Fenton catalytic activity and electrochemical performance

Porous CuO microspheres were prepared via a coordination precipitation route and exhibited superior photocatalytic activity and electrochemical performance.

Morphological enhancement to CuO nanostructures by electron beam irradiation for biocompatibility and electrochemical performance

This paper reports the effect of electron beam irradiation on CuO thin films synthesized by the successive ionic layer adsorption and reaction (SILAR) method on copper foil for supercapacitor and biocompatibility application. Pristine and irradiated samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and electrochemical study. Pristine and irradiated CuO films were pure monoclinic phase, with uniform nanostructures over the whole copper foil. After irradiation, CuO samples had formed innovative nanostructures. Biocompatibility of pristine and irradiated CuO samples suggest that CuO sample is non-toxic and ecofriendly. The specific capacitance of pristine and irradiated CuO strongly depends on surface morphology, and CuO electrodes after irradiation showed superior performance than pristine CuO. The highest specific capacitance of the 20kGy irradiated CuO nanoflowers exceeded 511Fg^-1 at 10mVs^-1 in 1M KOH electrolyte. Irradiated CuO samples also showed lower ESR, and were superior to other report electrical energy storage materials.