Synthesis of Porous NiO and ZnO Submicro- and Nanofibers from Electrospun Polymer Fiber Templates

Porous nickel oxide (NiO) and zinc oxide (ZnO) submicro- and nanofibers were synthesized by impregnating electrospun polyacrylonitrile (PAN) fiber templates with corresponding metal nitrate aqueous solutions and subsequent calcination. The diameter of the NiO and ZnO fibers was closely related to that of the template fibers and larger diameters were obtained when using the template fibers with larger diameter. SEM results showed that the NiO and ZnO fibers have a large amount of pores with diameters ranging from 5 nm to 20 nm and 50 nm to 100 nm, respectively. Energy dispersive X-ray (EDX) spectra and X-ray diffraction (XRD) patterns testified that the obtained materials were NiO and ZnO with high purity

Room temperature all-solid-state lithium batteries based on a soluble organic cage ionic conductor

All solid-state lithium batteries (SSLBs) are poised to have higher energy density and better safety than current liquid-based Li-ion batteries, but a central requirement is effective ionic conduction pathways throughout the entire cell. Here we develop a catholyte based on an emerging class of porous materials, porous organic cages (POCs). A key feature of these Li(+) conducting POCs is their solution-processibility. They can be dissolved in a cathode slurry, which allows the fabrication of solid-state cathodes using the conventional slurry coating method. These Li(+) conducting cages recrystallize and grow on the surface of the cathode particles during the coating process and are therefore dispersed uniformly in the slurry-coated cathodes to form a highly effective ion-conducting network. This catholyte is shown to be compatible with cathode active materials such as LiFePO(4), LiCoO(2) and LiNi(0.5)Co(0.2)Mn(0.3)O(2), and results in SSLBs with decent electrochemical performance at room temperature

Synthesis of Porous NiO and ZnO Submicro- and Nanofibers from Electrospun Polymer Fiber Templates

Abstract Porous nickel oxide (NiO) and zinc oxide (ZnO) submicro- and nanofibers were synthesized by impregnating electrospun polyacrylonitrile (PAN) fiber templates with corresponding metal nitrate aqueous solutions and subsequent calcination. The diameter of the NiO and ZnO fibers was closely related to that of the template fibers and larger diameters were obtained when using the template fibers with larger diameter. SEM results showed that the NiO and ZnO fibers have a large amount of pores with diameters ranging from 5 nm to 20 nm and 50 nm to 100 nm, respectively. Energy dispersive X-ray (EDX) spectra and X-ray diffraction (XRD) patterns testified that the obtained materials were NiO and ZnO with high purity.</p

Thermostable pectate lyase from Caldicellulosiruptor kronotskyensis provides an efficient addition for plant biomass deconstruction

To understand the enzymological basis for extremely thermophilic, biomass-degrading genus Caldicellulosiruptor metabolize pectin, a thermostable pectate lyase Pel-863 encoded by a gene cluster for hexose-containing polysaccharide metabolism in genome of C. kronotskyensis was studied. The pectate lyase of Caldicellulosiruptor was highly conserved and the representative Pel-863 was biochemically characterized, and the application for pectin containing biomass degradation was also studied. Pel-863 exhibited an optimal activity at 70 degrees C and pH 9.0 with Ca2+ as cofactor. It degraded polygalacturonic acid (PGA), methylated pectin and pectic biomass through endo-cleaving action. The respective V-max and K-m for Pel-863 were 172.8 U/mg and 0.60 g/L on PGA. FTIR and SEM analysis indicated that Pel-863 could remove most of pectin in hemp fiber with less damage compared to alkaline degumming. In addition, pre-digestion with Pel-863 improved glucose and xylose yield by 14.2% and 311.6% respectively for corn stalk, 6.5% and 55% for rice stalk compared with sole action of Novozymes Cellic CTec2. (C) 2015 Elsevier B.V. All rights reserved

Porous Electrode Materials for Zn-Ion Batteries: From Fabrication and Electrochemical Application

Porous materials as electrode materials have demonstrated numerous benefits for high-performance Zn-ion batteries in recent years. In brief, porous materials as positive electrodes provide distinctive features such as faster electron transport, shorter ion diffusion distance, and richer electroactive reaction sites, which improve the kinetics of positive electrode reactions and achieve higher rate capacity. On the other hand, the porous structures as negative electrodes also exhibit electrochemical properties possessing higher surface area and reducing local current density, which favors the uniform Zn deposition and restrains the dendrite formation. In view of their advantages, porous electrode materials for ZIB are expected to be extensively applied in electric and hybrid electric vehicles and portable electronic devices. In this review, we highlight the methods of synthesizing porous electrode materials and discuss the mechanism of action of porous structures as electrodes on their electrochemical properties. At the end of this review, the perspectives on the future development of porous materials in the field of electrochemical energy storage are also discussed

Unity of Opposite: Highly Emissive Luminogens in both Solution and Aggregate States toward Room Temperature Phosphorescence and Electroluminescence

Organic light-emitting materials, especially those with two-phase high emission, have attracted considerable attention for applications in bioimaging agents, sensors, optoelectronic devices, etc. Many fluorophores applied in such fields either emit brightly in dilute solution or in aggregate state, with the former often suffering from aggregation-caused quenching effect, and the latter falling dark at low concentrations. Herein, we overcame the dilemma by balancing the planar and distorted structures with various side units and achieved bright emission in both dilute solution (e.g., the absolute quantum yields (ФPL) = 90.2% in THF) and in aggregate states (e.g., ФPL=92.7% in powder state, ФPL = 95.3% in crystal). These luminescent mate-rials are demonstrated as promising guests embedded into host matrix to achieve efficient room temperature phosphores-cence, and these host-guest systems could be applied in the information encryption. Moreover, these luminogens could also be used as single-component emitting layers to construct non-doped organic light-emitting diodes, from which a maximum external quantum efficiency up to 4.75% with Commission International de L’Eclairge (CIE) coordinates of (0.15, 0.05), which is neatest to next generation ultra-high definition television (UHDTV) display standard, was realized. This work pro-vides a feasible strategy of balancing the planar and distorted structure of a luminogen toward highly efficient emission in both solution and solid states

MnO₂ Nanosheets Grown on Internal Surface of Macroporous Carbon with Enhanced Electrochemical Performance for Supercapacitors

Supercapacitor performance is strongly dependent on the utilization rate of electrode materials. In this paper, MnO₂ nanosheets (MONSs) have been grown on the inner surface of macroporous carbon (MPC) for increasing the utilization rate. The MPC is prepared from luffa sponge fibers. The MPC possesses closely arranged straight channels at the micrometer scale, which makes the MONSs be able to grow on the inner surface. Because of sufficient exposure toward electrolyte, the MONSs exhibit high mass specific capacitance at different loadings such as 1332 F/g (150 μg/cm²) and 354 F/g (5690 μg/cm²). Because of the presence of the large pores allowing the electrolyte solution to access easily, the active materials are capable of working at high loadings, obtaining areal specific capacitance as high as 2.9 F/cm². The assembled supercapacitors show a high specific energy of 194 μWh/cm² at the specific power of 4.5 mW/cm². As the luffa sponge is abundant and pollution-free in production, the MONSs/MPC is of high promise for supercapacitor application. The present method to grow the active materials on an inner surface to increase the utilization rate is also valuable for other applications, e.g., catalysis and Li-ion batteries