Recent Progress of Polyurethane-Based Materials for Oil/Water Separation
Gailan Guo, Libin Liu, Zhao Dang, Wenyuan Fang
With the development of society, oil pollution has become more and more serious, it is becoming a global issue to separate oil and water mixture. Currently, a variety of functional materials have been successfully prepared for oil/water separation. Among them, polyurethane is an attractive candidate due to its low cost, wear-resistance and excellent mechanical properties. This report summarizes the design strategy of polyurethane-based materials and their applications in oil/water separation. The progress made so far will guide further development of polyurethane-based materials for oil/water separation.
Keywords: Polyurethane; oil/water separation; membrane; foam
Electrochemical Performance of Lithium-Ion Capacitors Using Pre-Lithiated Multiwalled Carbon Nanotubes as Anode
Manyuan Cai, Xiaogang Sun, Yanyan Nie, Wei Chen, Zhiwen Qiu, Long Chen, Zhenhong Liu, Hao Tang
Pre-lithiated multiwalled carbon nanotube anode was prepared by internal short circuit approach(ISC) for 5 min, 30 min, 60 min and 120 min respectively. Lithium ion capacitors (LICs) were assembled by using pre-lithiated multiwalled carbon nanotubes as anodes and activated carbon (AC) as cathodes. The structure of multiwalled carbon nanotubes and electrodes were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical performance of pre-lithiated multiwalled carbon nanotube electrodes and pristine carbon nanotube electrodes were tested by galvanostatic charge/discharge and electrochemical impedance. The results indicated that pre-lithiation carbon nanotubes greatly improved the charge/discharge performance of LICs. The energy density was four times than conventional electric double-layer capacitors (EDLCs) at the current density of 100 mA/g. The LICs achieved a specific capacitance of 59.3 F/g at the current density of 100mA/g with 60min pre-lithiatiation process. The maximum energy density and power density was 96W h/kg and 4035 W/kg, respectively. The energy density still remained about 89.0% after 1000 cycles. The LIC showed excellent supercapacitor performance.
Keywords: Pre-lithiatiation; anode; multiwalled carbon nanotubes (MWCNTs); activated carbon (AC); lithium-ion capacitor
Rationally Designed Three-Dimensional NiMoO4/Polypyrrole Core–Shell Nanostructures for High-Performance Supercapacitors
Tingting Chen, Guangning Wang, Qianyan Ning
Electrodes of rationally designed composite nanostructures can offer many opportunities for the enhanced performance in electrochemical energy storage. This paper attempts to illustrate the design and production of NiMoO4/polypyrrole core–shell nanostructures on nickel foam to be used in supercapacitor via a facile hydrothermal and electrodeposition process. It has been verified that this novel nanoscale morphology has outstanding capacitive performances. While employed as electrodes in supercapacitors, the composite nanostructures showed remarkable electrochemical performances with a great areal capacitance (3.2 F/cm2 at a current density of 5 mA/cm2), and a significant cycle stability (80% capacitance retention after 1000 cycles). The above results reveal that the composite nanostructures may be a likely electrode material for high-performance electrochemical capacitors.
Keywords: Polypyrrole; NiMoO4; core–shell; supercapacitor
Synthesis and Characterization of Pb@GaS Core-Shell Fullerene-Like Nanoparticles and Nanotubes
Olga Brontvein, Lothar Houben, Ronit Popovitz-Biro, Moshe Levy, Daniel Feuermann, Reshef Tenne, Jeffrey M. Gordon
New types of core–shell nanoparticles are reported: Pb@GaS fullerene-like and nanotubular structures, achieved via the continuously high reactor temperatures and ultra-hot strong-gradient annealing environments created by highly concentrated sunlight. Structural and chemical characterizations suggest a formation mechanism where vaporized Pb condenses into nanoparticles that are stabilized as they become covered by molten GaS, the ensuing crystallization of which creates the outer layers. Hollow-core GaS fullerene-like nanoparticles and nanotubes were also observed among the products, demonstrating that a single solar procedure can generate a variety of core–shell and hollow nanostructures. The proposed formation mechanisms can account for their relative abundance and the characterization data.
Keywords: Core-shell; inorganic fullerene-like; nanotubes; gallium sulfide; Pb-filled; solar ablation
Optimized Assembly of Micro-/Meso-/Macroporous Carbon for Li–S Batteries
Qiong Tang, Heqin Li, Min Zuo, Jing Zhang, Yiqin Huang, Peiwen Bai, Jiaqi Xu, Kuan Zhou
In order to explore the effect of hierarchical porous carbon on the performances of Li–S batteries, we synthesized three kinds of micro-/meso-/macroporous carbon materials with different pore properties by facile hard-template method. Different from the majority of reports on porous carbon ensuing large specific surface area (SSA) and total pore volume, it was found that in the case of identically high sulfur content, the pore size distribution substantially influences the performances of Li–S batteries rather than the SSA and total pore volume. Furthermore, in the assembly of micro-/meso-/macropores, the micropore volume ratio to the total pore volume is dominant to the capabilities of batteries. Among the samples, the porous carbon carbonized with the precursor of sucrose at 950 oC presents the highest initial discharge specific capacity of 1327 mAh/g and retention of 630 mAh/g over 100 cycles at 0.2C rate along with the best rate capability. This sample possesses the largest micropore volume ratio of 47.54% but a medium SSA of 1217 m2/g and inferior total pore volume of 0.54 cm3/g. The abundant micropores effectively improve the conductivity of dispersed sulfur particles, inhibit the loss of sulfur series and enable the cathode to exhibit superior electrochemical performances.
Keywords: Li–S battery; micro-/meso-/macroporous carbon; specific surface area; total pore volume; pore size distribution
Preparation and Characterization of Nitrogen-Containing Cellular Activated Carbon for CO2 and H2 Adsorption
Weigang Zhao, Lu Luo, Mizi Fan
New monolithic nitrogen-containing microporous cellular activated carbon was successfully prepared from phenol-urea-formaldehyde (PUF) organic foam for CO2 and H2 adsorption and was characterized by thermogravimetric analysis (TG), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), a mechanical testing machine, N2-sorption and H2/CO2 sorption. The carbon yield was approximately 50% for carbonization and the burn off for activation ranged from 40% to 56%, which linearly increased with activation time. The macroporosity corresponded to the connected network of cells with diameters ranging from 100 μm to 600 μm, and the pinholes in the cell walls had diameters ranging from 1 μm to 2 μm. The micro/mesoporosity is located at the inner surface of the cells. Thus, higher adsorption kinetics than usual from activated carbon are expected. The developed carbon with the highest SBET (1674 m2/g) and highest VDR (0.86cm3/g) contained 1.5% nitrogen, had a CO2 adsorption capacity of 3.53 mmol/g at 298K, and had an H2 adsorption capacity of 1.9 wt.% at 77K, both at atmospheric pressure (1 bar), which were among the best in activated carbons from physical activation.
Keywords: Cellular activated carbon; nitrogen doping; CO2 capture; H2 storage
