The synthesis of layered double hydroxide (LDH) as electroactive material has been well reported; however, fabricating an LDH electrode with excellent electrochemical performance at high current density remains a challenge. In this paper, we report a 3D hierarchical porous flower-like NiAl-LDH grown on nickel foam (NF) through a liquid-phase deposition method as a high-performance binder-free electrode for energy storage. With large ion-accessible surface area as well as efficient electron and ion transport pathways, the prepared LDH-NF electrode achieves high specific capacity (1250 C g−1 at 2 A g−1 and 401 C g−1 at 50 A g−1) after 5000 cycles of activation at 20 A g−1 and high cycling stability (76.7% retention after another 5000 cycles at 50 A g−1), which is higher than those of most previously reported NiAl-LDH-based materials. Moreover, a hybrid supercapacitor with LDH-NF as the positive electrode and porous graphene nanosheet coated on NF (GNS-NF) as the negative electrode, delivers high energy density (30.2 Wh kg−1 at a power density of 800 W kg−1) and long cycle life, which outperforms the other devices reported in the literature. This study shows that the prepared LDH-NF electrode offers great potential in energy storage device applications.

High-Performance Hybrid Supercapacitor with 3D Hierarchical Porous Flower-like Layered Double Hydroxide Grown on Nickel Foam As Binder-Free Electrode

Currently, nanotechnology is referred to be one of the attractive research sectors in several countries because of its vast potential and commercial impact. Nanotechnology includes the investigation, development, fabrication, and processing of structures and materials on a nanoscale in various fields of science, health care, agriculture, technology, and industries. As such, it has provided a steady restructuring of related technologies. However, the irregularities and uncertainties in dimensions and chemical compositions, makes the viability of such materials questionable. Concerns have been inclined about the transport, destiny, and transformation of nanomaterials discharged into the environment. A critical analysis of the present phase of knowledge concerning the exposure and effects of nanomaterials has been discussed in-depth. In this review, different nanomaterials along with their applications have also been reviewed, that include graphene-based nanomaterials, carbon nanotubes, and their composites, nanoclay composites, nanostructured thin films, metal-organic frameworks, conducting polymers and their composites, MXenes, chalcogenide nanocrystals, and quantum dots. Besides, a few of the groundbreaking applications of nanomaterials for different sectors like human health, processes, photochemical process, energy conversion and energy storage, separation and purification processes, optoelectronics, etc. are discussed in detail with their chemsitry. Moreover, the unique characteristics and applications of nanomaterials, they inherently introduce challenges for their applications and large-scale production. Acknowledgment of the potential benefits and unknown dangers of nanomaterials is critically is critically analyzed and discussed in the manuscript.

Nanomaterials: Applications, waste-handling, environmental toxicities, and future challenges – A review

https://onlinelibrary.wiley.com/doi/epdf/10.1002/adtp.202000024

Advances in Antimicrobial Organic and Inorganic Nanocompounds in Biomedicine

Safe, therapeutically effective, and patient-compliant drug delivery systems are needed to design novel tools and strategies to combat the deadliest of diseases such as cancer, SARS, H7N9 avian influenza, and dengue infection The major challenges in drug delivery are cytotoxicity, poor biodistribution, insufficient functionality, ineffective drug incorporation in delivery devices, and subsequent drug release Clay minerals are a class of nanolayered silicates that have good biocompatibility, high specific surface area, chemical inertness, colloid, and thixotropy, and are attractive practical and potential nanomaterials in medicine These properties enable the usage of nanoclays as drug carriers for the delivery of antibiotics, antihypertensive drugs, anti-psychotic, and anticancer drugs The review examines the latest advances in nanoclay-based drug delivery systems and related applications in gene therapy and tissue engineering Clay minerals, particularly montmorillonite, kaolinite, and halloysite are used to delay and/or target drug release or even improve drug dissolution due to their surface charge Chemical modification of clay minerals such as intercalation of ions into the interlayer space of clay minerals or surface modification of clay minerals is a strategy to tune the properties of nanoclays for the loading and release of a drug The modified nanoclay can take up drugs by encapsulation, immobilization, ion exchange reaction, or electrostatic interactions Controlled drug release from the drug-clay originates from the incorporation and interactions between the drug and inorganic layers, including electrostatic interactions and hydrogen bonding Montmorillonite has proven non-toxic through hematological, biochemical, and histopathological analyses in rat Montmorillonite can also act as a potent detoxifier Halloysite nanotubes can bind synthetic and biological components such as chitosan, gelatin, and alginate innate nanocarriers for the improved loading and controlled release of drugs, proteins, and DNA The peculiar properties of clay nanoparticles lead to promising applications in drug delivery, gene delivery, tissue engineering, cancer and stem cell isolation, and bioimaging

Nanoclay-based drug delivery systems and their therapeutic potentials.

Inorganic/organic hybrid nanosystems have been increasingly developed for their versatility and efficacy at overcoming obstacles not readily surmounted by nonhybridized counterparts. Currently, hybrid nanosystems are implemented for gene therapy, drug delivery, and phototherapy in addition to tissue regeneration, vaccines, antibacterials, biomolecule detection, imaging probes, and theranostics. Though diverse, these nanosystems can be classified according to foundational inorganic/organic components, accessory moieties, and architecture of hybridization. Within this Review, we begin by providing a historical context for the development of biomedical hybrid nanosystems before describing the properties, synthesis, and characterization of their component building blocks. Afterward, we introduce the architectures of hybridization and highlight recent biomedical nanosystem developments by area of application, emphasizing hybrids of distinctive utility and innovation. Finally, we draw attention to ongoing clinical trials before recapping our discussion of hybrid nanosystems and providing a perspective on the future of the field.

Hybrid Nanosystems for Biomedical Applications.

Recent advancements in material technologies have promoted the development of various preparation strategies and applications of novel polymer–nanoclay composites. Innovative synthesis pathways have resulted in novel polymer–nanoclay composites with improved properties, which have been successfully incorporated in diverse fields such as aerospace, automobile, construction, petroleum, biomedical and wastewater treatment. These composites are recognized as promising advanced materials due to their superior properties, such as enhanced density, strength, relatively large surface areas, high elastic modulus, flame retardancy, and thermomechanical/optoelectronic/magnetic properties. The primary focus of this review is to deliver an up-to-date overview of polymer–nanoclay composites along with their synthesis routes and applications. The discussion highlights potential future directions for this emerging field of research.

A Review of the Synthesis and Applications of Polymer–Nanoclay Composites

A new kind of zeolite capsule complex with ferriferous oxide (Fe3O4) materials was prepared in this work. Its morphology was characterized via the scanning electron microscope (SEM), the high-resolution transmission electron microscopy (HRTEM), N2 adsorption analysis, and X-ray powder diffraction, respectively. The mesoporous nickel-based complex electrodes using substrate coating exhibited excellent energy storage properties through electrochemical testing. The high specific capacitance of 739.8 F g−1 was achieved at the current density of 1 A g−1 in a 6 M KOH solution. The good capacitance retention can retain 72.8% after 1000 cycles in a current density of 1 A g−1. The energy storage mechanism of the nickel-based complex electrodes was also analyzed. Furthermore, the asymmetrical supercapacitors (ASCs) were fabricated using the zeolite capsule complex with Fe3O4 as positive electrodes and the AC as negative electrodes, which performs high specific capacitance, outstanding energy density, superb power density, excellent cycle life, and small internal impedance. Those results suggest that the mesoporous nickel-based zeolite capsule complex with Fe3O4 as an electrode would be an ideal candidate material for supercapacitor applications.

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Mesoporous Nickel-Based Zeolite Capsule Complex with Fe3O4 as Electrode for Advanced Supercapacitor

Manganese and cerium (Mn-Ce) oxides were prepared under nitrogen and high-temperature oxidation via a bath precipitation method as materials for electrode assemblies in supercapacitors. The prepared Mn-Ce oxide composite was demonstrated to have a high specific capacitance of 163.7 F g−1 with 78.4% cyclic stability after 3000 cycles at a current density of 1 A g−1. Electrochemical impedance spectroscopy confirms that MnO2 improves the conductivity of CeO2. Results from XPS analysis suggest that the introduction of MnO2 enhances the concentrations of oxygen vacancies. Finally, band structure, density of states and Mulliken population were calculated using density functional theory, and the findings are consistent with the experimental and characterization results. Because of their excellent performances, Mn-Ce bimetallic oxides are promising electrode materials for supercapacitors.

Fabrication of Mn-Ce Bimetallic Oxides as Electrode Material for Supercapacitors with High Performance

In this work, the Ni-MOFs of electrode material has been synthesized, characterized and studied for the electrochemical properties of electrode materials. The effects of the doping amount of Ni, calcination temperature and time were studied in detail. The results suggested that the electrochemical properties were obviously improved by the Ni-MOFs of electrode material and the best preparation conditions can also improve the electrochemical properties of electrode materials. These results open a way for the design of tailored MOFs as electrode materials for supercapacitors.

https://iopscience.iop.org/article/10.1088/1757-899X/317/1/012070/pdf

Electrochemical Performance of Ni-MOFs for Supercapacitors

A series of bimetallic oxides electrode materials were proposed to boost the supercapacitor performance using the density functional theory (DFT) in combination with the electrochemical tests. This work provides a guiding role for exploring energy storage materials with high performance. Based on the plane wave ultra-soft pseudo-potential (PWPP) and general gradient approximate (GGA) in DFT, the electronic and the crystal structures of various strontium bismuth oxides (β-Bi2O3, SrBi2O4, Sr2Bi2O5 and SrBiO3) were calculated, and the corresponding energy bands were compared. The simulation results show that SrBiO3 has a smaller band gap than the other three oxides, due to the significant hybridization of the electronic density of SrBiO3. The prepared strontium bismuth oxide materials (SrBi2O4, Sr2Bi2O5 and SrBiO3) were characterized using scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD), respectively. In the electrochemical measurement of 6M KOH solution, SrBiO3 presents the highest specific capacity of 810.93F g−1 (i.e. 126.95 mAh g−1) at a current density of 1A g−1. The capacitance retention rate of SrBiO3 is 80.11 % after 2000 cycles, which indicates that it has the useful properties of cyclic stability. All the results suggest that SrBiO3 will be an excellent candidate in electrode materials for the battery-type supercapacitors.

Yinghui Han

Papers

A Review of the Synthesis and Applications of Polymer–Nanoclay Composites

Mesoporous Nickel-Based Zeolite Capsule Complex with Fe3O4 as Electrode for Advanced Supercapacitor

Fabrication of Mn-Ce Bimetallic Oxides as Electrode Material for Supercapacitors with High Performance

Electrochemical Performance of Ni-MOFs for Supercapacitors

High-performance strontium and bismuth bimetallic oxides electrode：combine first-principles calculations with electrochemical tests