Designing hard carbon microsphere structure via halogenation amination and oxidative polymerization reactions for sodium ion insertion mechanism investigation.

Hard carbon as a negative electrode material for sodium-ion batteries (SIBs) has great commercial potential and has been widely studied. The sodium-ion intercalation in graphite domains and the filling of closed pores in the low voltage platform region still remain a subject of controversy. We have successfully constructed hard carbon materials with a pseudo-graphitic structure by using polymerizable p-phenylenediamine and dichloromethane as carbon sources. This was achieved by a halogenated amination reaction and oxidative polymerization. It was found that the capacity of hard carbon materials mainly originates from intercalation into graphite domains. The study found that the prepared hard carbon could store 339.33 mAh g-1 of sodium in a reversible way at a current density of 25 mA g-1, and it had an initial coulomb efficiency of 80.23%. It even maintained a reversible sodium storage capacity of 125.53 mAh g-1 at a high current density of 12.8 A g-1. Based on the analysis of hard carbon structure and electrochemical performance, it was shown that the materials conform with an "adsorption-intercalation" mechanism for sodium storage.

Two-dimensional layered lithium lanthanum titanium oxide/graphene-like composites as electrodes for lithium-ion batteries.

Perovskite-structured (ABO3) lithium lanthanum titanate (LixLa(2-x)/3TiO3, LLTO) is widely used in all solid state lithium ion batteries due to its high ionic conductivity. In this study, a two-dimensional LLTO nanosheet/graphene (LLTO/C) nanosheet composite has been designed as an electrode material for lithium-ion batteries (LIBs). LLTO/C not only exhibits the ionic conductivity properties of perovskite-type LLTO, but the graphene between the layers of LLTO nanosheets also endows the material with additional electronic conductivity. Moreover, LLTO@C-600 exhibits an excellent rate capability as the electrode for delithiation with a high specific capacity of 350 mA h g-1 at 20 mA g-1, and 70% of the specific capacity can be maintained at 1.0 A g-1 after 800 cycles. The excellent electrochemical performances can be attributed to the superior interficial capacitive Li+ storage capability.

Tuning the Defects of Two-Dimensional Layered Carbon/TiO2 Superlattice Composite for a Fast Lithium-Ion Storage.

Defect engineering is one of the effective ways to improve the electrochemical property of electrode materials for lithium-ion batteries (LIB). Herein, an organic functional molecule of p-phenylenediamine is embedded into two-dimensional (2D) layered TiO2 as the electrode for LIB. Then, the 2D carbon/TiO2 composites with the tuning defects are prepared by precise control of the polymerization and carbothermal atmospheres. Low valence titanium in metal oxide and nitrogen-doped carbon nanosheets can be obtained in the carbon/TiO2 composite under a carbonization treatment atmosphere of N2/H2 gas, which can not only increase the electronic conductivity of the material but also provide sufficient electrochemical active sites, thus producing an excellent rate capability and long-term cycle stability. The prepared composite can provide a high capacity of 396.0 mAh g-1 at a current density of 0.1 A g-1 with a high capacitive capacity ratio. Moreover, a high specific capacity of 80.0 mAh g-1 with retention rate of 85% remains after 10,000 cycles at 3.0 A g-1 as well as the Coulomb efficiency close to 100%. The good rate-capability and cycle-sustainability of the layered materials are ascribed to the increase of conductivity, the lithium-ion transport channel, and interfacial capacitance due to the multi-defect sites in the layered composite.

Rapid Electrochemical Activation of V2 O3 @C Cathode for High-Performance Zinc-Ion Batteries in Water-in-Salt Electrolyte.

Aqueous Zn-ion batteries (ZIBs), with the advantages of low cost, high safety, and high capacity, have great potential for application in grid energy storage and wearable flexible devices. However, their commercial application is still restricted by their inferior long-term cycling stability, Zn dendrite formation, and the decomposition of aqueous electrolyte. In this study, a Zn|Zn(CF3 SO3 )2 +LiTFSI|V2 O3 @C cell is constructed to address the above issues. The V2 O3 @C electrode can be fully oxidized into amorphous V2 O5 @C simultaneously with Zn2+ and H2 O co-insertion. The cell delivers a high specific capacity of more than 240 mAh g-1 at 3 A g-1 , with extraordinary coulombic efficiency and capacity retention. The excellent electrochemical performances are attributed to synergistic effects between the V2 O3 @C electrode and the water-in-salt electrolyte with enhanced stability and improved interface reaction kinetics. Systematic improvements of this architecture indicate much promise for application.

Nanocellulose Based Filtration Membrane in Industrial Waste Water Treatment: A Review.

In the field of industrial wastewater treatment, membrane separation technology, as an emerging separation technology, compared with traditional separation technology such as precipitation, adsorption, and ion exchange, has advantages in separation efficiency, low energy consumption, low cost, simple operation, and no secondary pollution. The application has been expanding in recent years, but membrane fouling and other problems have seriously restricted the development of membrane technology. Natural cellulose is one of the most abundant resources in nature. In addition, nanocellulose has characteristics of high strength and specific surface area, surface activity groups, as well as being pollution-free and renewable, giving it a very wide development prospect in many fields, including membrane separation technology. This paper reviews the current status of nanocellulose filtration membrane, combs the widespread types of nanocellulose and its derivatives, and summarizes the current application of cellulose in membrane separation. In addition, for the purpose of nanocellulose filtration membrane in wastewater treatment, nanocellulose membranes are divided into two categories according to the role in filtration membrane: the application of nanocellulose as membrane matrix material and as a modified additive in composite membrane in wastewater treatment. Finally, the advantages and disadvantages of inorganic ceramic filtrations and nanocellulose filtrations are compared, and the application trend of nanocellulose in the filtration membrane direction is summarized and discussed.

Controllable growth of carbon nanosheets in the montmorillonite interlayers for high-rate and stable anode in lithium ion battery.

A novel insertable and pseudocapacitive Li+ ion material for highly ordered layered montmorillonite/carbon is explored in the present study. The commercially available protonated montmorillonite and 3,3'-diaminobenzidine act as starting materials to synthesize the layered material via hydrothermal intercalation, oxidative polymerization and carbonization. This method of preparing montmorillonite/carbon nanocomposite exhibits several advantages. To be specific, raw materials are low cost and naturally abundant; the montmorillonite can undergo proton exchange easily to form a permutable proton-type material, and the protons in the layered nanocomposite can be directly substituted by the polymerizable molecules (e.g., 3,3'-diaminobenzidine). Accordingly, a sheet-like montmorillonite/carbon layered nanocomposite is achieved with the carbon stacking on the montmorillonite substrate for the intercalation behavior. As revealed from the electrochemical results, montmorillonite/carbon nanocomposite can deliver a high reversible capacity of 1432 mA h g-1 at 50 mA g-1 and superior rate capacity of 920 mA h g-1 at 10 000 mA g-1 for the lithium ion battery. Furthermore, the full cell with LiFePO4 as cathode and montmorillonite/carbon as anode maintains 94% capacity retention over 50 cycles as well as high coulombic efficiency.

Intercalation of Carbon Nanosheet into Layered TiO2 Grain for Highly Interfacial Lithium Storage.

Interfacial energy storage contributes a new mechanism to the emergence of energy storage devices with not only a high-energy density of batteries but also a high-power density of capacitors. In this study, success was achieved in preparing a highly ordered two-dimensional (2D) carbon/TiO2 (C/TiO2) nanosheet composite using commercially available organic molecules with multifunctional groups and taking advantage of the wedge effects, oxidative polymerization, and carbonization. An experiment was conducted to validate the excellent performance of this 2D composite with respect to interfacial energy storage. The coin cell with 2D C/TiO2 nanosheet composite demonstrates a specific capacity of as high as 510 mAh g-1 and a high specific energy of 390.9 Wh kg-1 at a specific power of 75.9 W kg-1 with a current density of 0.1 A g-1, and it also remains 39.0 Wh kg-1 at a specific power of 8.2 kW kg-1 with a high current density of 12.8 A g-1. The excellent electrochemical performance can be attributed to the superior artificial interface capacitive Li+ storage capability, which would bridge the energy and power density gap between batteries and capacitors. Meanwhile, there are two varieties of carbon derivatives, 2D carbon nanosheet stacks and exfoliated carbon nanosheets, which can be obtained by wet-chemical etching and mechanical peeling. The experimental route is simple from commercially available raw materials, and it could be scalable at a low cost and large scale, which makes it suitable for application in various fields such as energy storage, nanocatalysis, sensors, and so on.

Two-Dimensional Layered Ultrathin Carbon/TiO2 Nanosheet Composites for Superior Pseudocapacitive Lithium Storage.

Intercalation of carbon nanosheets into two-dimensional (2D) inorganic materials could enhance their properties in terms of mechanics and electrochemistry, but sandwiching these two kinds of materials in an alternating sequence is a great challenge in synthesis. Herein, we report a novel strategy to construct TiO2 nanosheets into 2D pillar-layer architectures by employing benzidine molecular assembly as pillars. Then, 2D carbon/TiO2 nanosheet composite with a periodic interlayer distance of 1.1 nm was obtained following a polymerization and carbonization process. This method not only alleviates the strain arising from the torsion of binding during carbonization but also hinders the structural collapse of TiO2 due to the intercalation of the carbon layer by rational control of annealing conditions. The composite material possesses a large carbon/TiO2 interface, providing abundant active sites for ultrafast pseudocapacitive charge storage, thus displaying a superior high-rate performance with a specific capacity of 67.8 mAh g-1 at a current density of 12.8 A g-1 based on the total electrode and excellent cyclability with 87.4% capacity retention after 3000 cycles.

An all-nanosheet OER/ORR bifunctional electrocatalyst for both aprotic and aqueous Li-O2 batteries.

Rechargeable lithium-oxygen (Li-O2) batteries are receiving intense interest because of their high energy density. A highly efficient catalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is a key factor influencing the performance of Li-O2 batteries. In this work, a facile synthesis of an all-nanosheet architecture electrocatalyst constructed from a monolayer ruthenium dioxide (RuO2) nanosheet with a nitrogen doped sulfonated graphene nanosheet (RuO2-NS-GNS) has been developed for Li-O2 batteries. This complex catalyst displays excellent activity towards the ORR and OER in both aprotic and aqueous Li-O2 batteries. A low overpotential around 1.0 V during the discharge/recharge process is obtained for the aprotic Li-O2 battery with RuO2-NS-GNS. Meanwhile, linear sweep voltammetry curves show that the OER and ORR potentials are 1.45 V and 0.81 V in an alkaline solution (1 M LiOH-5 M LiNO3) for RuO2-NS-GNS, respectively. Both aprotic and aqueous Li-O2 batteries with RuO2-NS-GNS exhibit stable cyclability and low round-trip overpotential without obvious degradation at a limited specific capacity of 1000 mA g-1. The advanced electrochemical performance of RuO2-NS-GNS in both aprotic and aqueous Li-O2 batteries can be attributed to the increased catalytic sites and synergistic effect arising from RuO2 and NS-GNS nanosheets.

Fabrication of high-quality amorphous silicon film from cyclopentasilane by vapor deposition between two parallel substrates.

Cyclopentasilane converts into amorphous silicon film between two parallel substrates under atmospheric pressure by thermal decomposition at 350-400 °C, which combines the advantages of high throughput with cost reduction and high quality film formation.

Selected deposition of high-quality aluminum film by liquid process.

For generation of a fine aluminum pattern by conventional vacuum processing, it is necessary not only to use complex and costly instruments but also to perform an additional etching process, which may result in physical and chemical damage to the target film surface. Herein we report a simple solution process for the selected deposition of an Al pattern. Al is obtained from the decomposition of alane under dehydrogenation catalysis of a Pt nanocrystalline pattern on a substrate at ∼105-120 °C, while the self-decomposition of alane in solution is avoided in the presence of high-boiling-point amine. This deposited film generates Al crystals with a diameter of several hundred nanometers, following an epitaxial growth to a continual film. The obtained film shows high conductivity, with a resistivity close to that of bulk Al.

Deposition of platinum patterns by a liquid process.

In contrast to the traditional chemical vapor deposition technique under high vacuum, we introduce a deposition method in liquid to prepare Pt patterns on substrate near 100 °C by seed growth.

Preparation of large thermally stable platinum nanocubes by using solvent-thermal reaction.

We describe the synthesis of single-crystalline Pt nanocubes with a large diameter (around 35 nm) using a solvent-thermal reaction in a polarity-controlled mixture of 1-butanol, toluene, and N,N-dimethylformamide at 185 °C.

Control of stripelike and hexagonal self-assembly of gold nanoparticles by the tuning of interactions between triphenylene ligands.

We describe the self-assembly of gold nanoparticles (Au NPs) protected with newly synthesized discotic liquid crystalline molecules of hexaalkoxy-substituted triphenylene (TP) in mixed toluene/methanol solvent. The stripelike (i.e., 2D consisting of linear 1D in stripe) self-assembly is realized successfully by the aid of pi-pi stacking of TP ligand on Au NPs. The smaller Au NPs with TP (AuTP) or the longer alkyl chain between TP and the gold core provide more free spaces among TP moieties. These spaces allow easy insertion of TP on adjacent AuTPs to lead an interparticle pi-pi interaction to form the stripelike arrangement. The solvent hydrophilicity can also serve as a controlled index to tune arrangement among stripelike, hexagonal close packed (hcp), or disorder. We have changed the solvent hydrophilicity by changing the ratio of methanol to toluene, which affects the balance of solution of AuTP (in toluene) and deposition (in methanol). The larger space between TPs and appropriate solvent hydrophilicity realize stripelike self-assembly caused by a strong pi-pi interaction between TPs, which was characterized by TEM, as well as fluorescence, dynamic light scattering, and 1H NMR spectra.

Preparation of single-crystalline platinum nanowires with small diameters under mild conditions.

We report a convenient method to synthesize single-crystalline platinum nanowires with high aspect ratio of ca. 2.0 nm diameter by sophisticated and precise control of Pt(0) nuclei and their growth.

Self-assembly of discotic liquid crystalline molecule-modified gold nanoparticles: control of 1D and hexagonal ordering induced by solvent polarity.

Gold nanoparticles fully coated with discotic liquid crystalline molecules of hexaalkoxy-substituted triphenylene (Au-TP) have been synthesised, the self-assembled structure of which could be controlled (hexagonal or 1D nanochain) just by altering the ratio of methanol to toluene in the solvent.