Boron-Doped Graphene as Anion-Trapping Reagent in Poly(ethylene oxide)-Based Solid-State Electrolyte.

Although many protocols have been developed to enhance the ionic conductivity and lithium-ion transference numbers of the solid polymer electrolyte, it is still challenging to improve them simultaneously. Herein, we design and prepare boron-doped graphene (BG) as an anion trapper and blend it within a poly(ethylene oxide) (PEO)-based electrolyte. The well-dispersed BG sheets can reduce the crystallinity of PEO and afford numerous Lewis acid sites to effectively accelerate the dissociation of the lithium salt and trap the anions.

Surface coating engineering of titanate anodes based on tannic acid-formaldehyde polymer chelating bismuth ions for advanced sodium-ion capacitors.

As a battery-type anode material for sodium ion capacitors (SICs), titanate (HTiO·HO, HTO) exhibits good rate capability due to its layered structure, easy to insert Na ions and low potential during sodium-ion storage. However, the structure is unstable due to the lattice distortion resulting from the irreversible embedment of Na in the process of sodium storage. So there is a significant mismatch between the dynamic reaction of the HTO anode and the capacitive cathode.

Dual Design on Hierarchically Hollow MoTe/C with Ion/Electron Channel Engineering for High-Performance Sodium Storage.

Transition-metal tellurides have been investigated as novel anode materials for application in sodium-ion batteries (SIBs) due to their rich active sites and unique and controllable layered nanostructures. However, the weak structural strength and inferior intercalation/deintercalation kinetics inhibit the development of transition-metal tellurides. In this work, MoTe/C composites with two different hollow nanostructures are designed and prepared.

Fluorine-Terminated Self-Assembled Monolayers Grafted Graphite Anode Inducing a LiF-Dominated SEI Inorganic Layer for Fast-Charging Lithium-Ion Batteries.

The electrochemical kinetic processes of Li ions, including the desolvation of the Li ions from the electrolyte to the solid electrolyte interphase (SEI), the transportation of desolvated Li ions across the SEI, and the charge transfer at the interface between the SEI and graphite, determine the rate performance and cycling stability of the graphitic anode in lithium-ion batteries (LIBs). In this work, fluorine-terminated self-assembled monolayers were grafted on the surface of spherical graphite particles to regulate the chemical composition and structure of SEI formed on the graphite surface in the presence of conventional ester electrolytes. The comprehensive characterization and first-principles calculation results illustrate that a uniform LiF-dominated SEI film can be generated on the as-functionalized graphite anode due to the carbon-fluorine bonds' cleavage of fluorine-terminated self-assembled monolayers.

Flexible Fluorinated Graphene/Poly(vinyl Alcohol) Films toward High Thermal Management Capability.

Graphene is widely used in heat dissipation, owing to its inherently high in-plane thermal conductivity and excellent mechanical properties. However, its poor cross-plane thermal conductivity limits its use in some electronic applications. The electron distribution of graphene and the interaction with the base material can be greatly altered by introducing F, the most electronegative element, giving fluorinated graphene oxide (FG) with a high thermal conductivity.

Entropy-Driven Morphology Regulation of MAX Phase Solid Solutions with Enhanced Microwave Absorption and Thermal Insulation Performance.

Morphology regulation and composition design have proved to be effective strategies for the fabrication of desirable microwave absorbers. However, it is still challenging to precisely control the microstructure and components of MAX phases. Herein, an entropy-driven approach, a transition from irregular grains (low entropy) to sheet structure (high entropy), is proposed to modulate the morphology of MAX phases.

Quenching modification of NiFe layered double hydroxides as efficient and highly stable electrocatalysts for the oxygen evolution reaction.

Nickel- and iron-containing layered double hydroxides (NiFe-LDHs) are prospective electrocatalysts for the oxygen evolution reaction (OER), but they suffer from poor electrical conductivity and inaccessible active sites. Herein, we employ a facile and efficient quenching strategy to modify the morphology and surface characteristics of NiFe-LDHs by rapid cooling in a series of salt solutions. After quenching in a SnCl solution, the modified NiFe-LDHs exhibit a low overpotential of 204 mV at a current density of 10 mA·cm and Tafel slope of 58.

Removal of organophosphorus agents atomically dispersed Co on nitrogen-doped graphene: catalytic degradation and adsorption.

In this work, we disperse Co atomically on three-dimensional networks of N-doped graphene (3DNG) through the impregnation of 3DNG with Co(Ac)·4HO solution followed by rapid pyrolysis. The structure, morphology and composition of the as-prepared composite, namely ACo/3DNG, are characterized. The atomically dispersed Co and enriched Co-N species afford the ACo/3DNG with unique catalytic activity for hydrolysis of organophosphorus agents (OPs), and the network structure and super-hydrophobic surface of 3DNG ensures excellent physical adsorption capacity.

Vapor-phase derived ultra-fine Bismuth nanoparticles embedded in carbon nanotube networks as anodes for sodium and potassium ion batteries.

Bismuth (Bi) is a promising material as the anode for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) due to its characteristics such as reasonable price and high theoretical volumetric capacity (3800 mAh cm). Nevertheless, considerable drawbacks have hindered the practical applications of Bi, including its relatively low electrical conductivity and inevitable volumetric change during the alloying/dealloying processes. To solve these problems, we proposed a novel design:Bi nanoparticles were synthesized via a single-step low-pressure vapor-phase reaction and embedded onto the surfaces of multi-walled carbon nanotubes (MWCNTs).

Oxidative Cleavage of β-O-4 Linkage in Lignin via Co Nanoparticles Embedded in 3DNG as Catalyst.

The cleavage of β-O-4 linkage in lignin is one of the key steps for oxidative conversion of lignin to low-molecular-weight aromatics. Herein, Co nanoparticles embedded in three-dimensional network of nitrogen-doped graphene (Co/NG@3DNG-X) were prepared through an immersion-pyrolysis procedure, in which X denotes the pyrolysis temperature. The detailed characterization of Co/NG@3DNG-X shows that the Co nanoparticles are coated with a few layers of nitrogen-doped graphene (NG) sheets that are further embedded in 3DNG matrix.

Catalytic Oxidation of Veratryl Alcohol Derivatives Using RuCo/rGO Composites.

Chemoselectively oxidizing C -OH to C=O has been considered as a key step for the oxidative depolymerization of lignin. In this work, we design and prepare a series of composites of RuCo alloy nanoparticles and reduced graphene oxide (RuCo/rGO) with different Ru to Co ratios and explore their catalytic activities in the oxidation of veratryl alcohol derivatives, which usually serve as the model compounds for studying lignin oxidation. It is illustrated that the Ru to Co ratio determines the morphology and average size of the RuCo alloy nanoparticles on rGO, and the overall catalytic activities of the composites.

Hydrolysis of Organophosphorus Agents Catalyzed by Cobalt Nanoparticles Supported on Three-Dimensional Nitrogen-Doped Graphene.

Catalytic chemical degradations and many other methodologies have been explored for the removal and/or degradation of organophosphorus agents (OPs) that are often used as pesticides, nerve agents, and plasticizers. To explore more efficient and recyclable catalysts for the removal and/or degradation of OPs, we fabricate the composites of cobalt nanoparticles and three-dimensional nitrogen-doped graphene (Co/3DNG). We demonstrate that OPs can be hydrolyzed efficiently at ambient temperature by the Co/3DNG.

Core-Shell PMIA@PVdF-HFP/AlO Nanofiber Mats Coaxial Electrospun on LiFePO Electrode as Matrices for Gel Electrolytes.

Gel electrolytes show certain advantages over conventional liquid and solid electrolytes, but their mechanical strength and surface adhesion to the electrode remain to be improved. To address the challenges, we design and fabricate herein the core-shell nanofiber mats on the LiFePO electrode as matrices for gel electrolytes, in which the core is poly(-phenylene isophthalamide) (PMIA) nanofiber and the shell are composite of AlO nanoparticles and poly(vinylidene fluoride--hexafluoropropylene) (PVdF-HFP). The mechanical property of the core-shell polymeric nanofiber mats and their surface interaction with LiFePO electrode are characterized complementarily using dynamic thermomechanical analysis and scanning electron microscopy.

Hydrated vanadium pentoxide/reduced graphene oxide composite cathode material for high-rate lithium ion batteries.

As well-known, hydrated vanadium pentoxide (VO·nHO) has a larger layer spacing than orthogonal VO, which could offer more active sites to accommodate lithium ions, ensuring a high specific capacity. However, the exploration of VO·nHO cathode is limited by its inherently low conductivity and slow electrochemical kinetics, leading to a significant decrease in capability. Herein, we prepared VO·nHO/reduced graphene oxide (rGO) composite with low rGO content (8 wt%) via a simple yet effective dual electrostatic assembly strategy.

Graphene quantum dots in photodynamic therapy.

Graphene quantum dots (GQDs) have shown great promise in a variety of medical applications. Recently, it has been found that GQDs are also beneficial for photodynamic therapy (PDT). However, the findings of GQDs as PDT agents have been controversial in the literature.

Morphology Design of Co-electrospinning MnO-VN/C Nanofibers for Enhancing the Microwave Absorption Performances.

To enhance microwave loss abilities, constructing composites with one-dimensional (1D) structure is an excellent scheme. In this work, a high-efficiency microwave absorber of MnO nanograins decorated vanadium nitride/carbon nanofibers (MnO-VN/C NFs) was successfully prepared for the first time via co-electrospinning technology and subsequent nitriding treatment. Studying in detail the specific relationship between nitriding time and the morphology of the as-prepared NFs, the precipitations of MnO nanoparticles with tailored structures were attached on the surface of VN/C NFs to optimize their electromagnetic parameters.

A High-Performance Primary Nanosheet Heterojunction Cathode Composed of Na MnO Tunnels and Layered Na Mn O for Na-Ion Batteries.

Owing to its large capacity and high average potential, the structure and reversible O-redox compensation mechanism of Na Mn O have recently been analyzed. However, capacity fade and low coulombic efficiency over multiple cycles have also been found to be a problem, which result from oxygen evolution at high charge voltages. Herein, a Na MnO ⋅Na Mn O heterojunction of primary nanosheets was prepared by a sol-gel-assisted high-temperature sintering method.

Dual Role of Graphene Quantum Dots in Active Layer of Inverted Bulk Heterojunction Organic Photovoltaic Devices.

Graphene quantum dots (GQDs) have shown broad application prospects in the field of photovoltaic devices due to their unique quantum confinement and edge effects. Here, we prepared GQDs by a photon-Fenton reaction as reported in our previous work, which has great advantage in the preparation scale. The photoelectric properties of the inverted hybrid solar cells based on poly(3-hexylthiophene) (P3HT):(6,6)-phenyl-C butyric acid methylester (PCBM):GQDs and P3HT:GQDs with different contents of GQDs as the active layers are demonstrated, as well as their morphology and structure by atomic force microscopy images.

Hierarchical TiO nanoarchitectures on Ti foils as binder-free anodes for hybrid Li-ion capacitors.

Hybrid Li-ion capacitor (LIC) draws more attention as novel energy storage device owing to its high power density and high energy density. Designing three-dimensional electrode materials is beneficial for improving electrochemical performance of LICs. Herein, an improved hydrothermal method combined with an ion-exchange reaction is used to manufacture oxygen vacancies (OVs)-doping TiO (TiO) nanowires/nanosheets (NWS) on Ti-foil.

Separating graphene quantum dots by lateral size through gel column chromatography.

Graphene quantum dots (GQDs) prepared through photo-Fenton reaction of graphene oxide are separated gel column chromatography. The as-separated GQDs were selectively introduced into the active layer of organic solar cells and achieved an enhancement of power conversion efficiency (PCE).

Flexible micro-supercapacitors assembled via chemically reduced graphene oxide films assisted by a laser printer.

Flexible micro-supercapacitors (MSCs) as power suppliers are important for portable and wearable electronic devices. Despite enormous efforts made, a simple, inexpensive high-throughput technique of graphene-based MSCs is still challenging. In this work, flexible MSCs are fabricated through commercial laser printing of the interdigital configuration of reduced graphene oxide-graphene oxide-reduced graphene oxide (rGO-GO-rGO) where the conductive rGO works as the electrode and the insulated GO serves as the separator.

Composites of Layered M(HPO) (M = Zr, Sn, and Ti) with Reduced Graphene Oxide as Anode Materials for Lithium Ion Batteries.

Tetravalent metal phosphates (M(HPO), M = Zr, Sn, and Ti) have robust layered structures with interlayer d spacings over 7.5 Å, but show poor electrical conductivity. On the other hand, single-atomic-layered reduced graphene oxide (rGO) sheets exhibit a high electrical conductivity.

Composites of Graphene Quantum Dots and Reduced Graphene Oxide as Catalysts for Nitroarene Reduction.

Composites of graphene quantum dots (GQDs) and reduced graphene oxide (rGO) with unique three-dimensional (3D) structure are prepared and their catalytic activities for reduction of nitroarenes are explored. We demonstrate that the 3D GQDs/rGO composites are more active in nitroarene reduction than GQDs and rGO. Some of them are even more active than the Ag-embedded calcium alginate (Ag/CA) or Au-embedded calcium alginate (Au/CA) catalysts.

Graphene Quantum Dots Downregulate Multiple Multidrug-Resistant Genes via Interacting with Their C-Rich Promoters.

Multidrug resistance (MDR) is the major factor in the failure of many forms of chemotherapy, mostly due to the increased efflux of anticancer drugs that mediated by ATP-binding cassette (ABC) transporters. Therefore, inhibiting ABC transporters is one of effective methods of overcoming MDR. However, high enrichment of ABC transporters in cells and their broad substrate spectra made to circumvent MDR are almost insurmountable by a single specific ABC transporter inhibitor.

Photothermally Driven Refreshable Microactuators Based on Graphene Oxide Doped Paraffin.

Actuators based on phase change materials (paraffin) can simultaneously produce large stroke length and large force due to thermal expansion, but the low thermal conductivity of paraffin requires high power input and long actuation time. The graphene oxide (GO) doped paraffin dynamic actuator addresses the key challenges in the design of thermal phase change actuators: Thermal conductivity and light absorbing are increased, and the response time is reduced compared to the standard phase change actuator designed with metal heating resistors. The thermal properties of GO-paraffin composites with varied loading amount are characterized to confirm the optimal loading amount of 1.