High-Potential Metalless Nanocarbon Foam Supercapacitors Operating in Aqueous Electrolyte.

Light-weight graphite foam decorated with carbon nanotubes (dia. 20-50 nm) is utilized as an effective electrode without binders, conductive additives, or metallic current collectors for supercapacitors in aqueous electrolyte. Facile nitric acid treatment renders wide operating potentials, high specific capacitances and energy densities, and long lifespan over 10 000 cycles manifested as 164.5 and 111.8 F g-1 , 22.85 and 12.58 Wh kg-1 , 74.6% and 95.6% capacitance retention for 2 and 1.8 V, respectively. Overcharge protection is demonstrated by repetitive cycling between 2 and 2.5 V for 2000 cycles without catastrophic structural demolition or severe capacity fading. Graphite foam without metallic strut possessing low density (≈0.4-0.45 g cm-3 ) further reduces the total weight of the electrode. The thorough investigation of the specific capacitances and coulombic efficiencies versus potential windows and current densities provides insights into the selection of operation conditions for future practical devices.

Silicon Derived from Glass Bottles as Anode Materials for Lithium Ion Full Cell Batteries.

Every year many tons of waste glass end up in landfills without proper recycling, which aggravates the burden of waste disposal in landfill. The conversion from un-recycled glass to favorable materials is of great significance for sustainable strategies. Recently, silicon has been an exceptional anode material towards large-scale energy storage applications, due to its extraordinary lithiation capacity of 3579 mAh g-1 at ambient temperature. Compared with other quartz sources obtained from pre-leaching processes which apply toxic acids and high energy-consuming annealing, an interconnected silicon network is directly derived from glass bottles via magnesiothermic reduction. Carbon-coated glass derived-silicon (gSi@C) electrodes demonstrate excellent electrochemical performance with a capacity of ~1420 mAh g-1 at C/2 after 400 cycles. Full cells consisting of gSi@C anodes and LiCoO2 cathodes are assembled and achieve good initial cycling stability with high energy density.

Silicon and Carbon Nanocomposite Spheres with Enhanced Electrochemical Performance for Full Cell Lithium Ion Batteries.

Herein, facile synthesis of monodisperse silicon and carbon nanocomposite spheres (MSNSs) is achieved via a simple and scalable surface-protected magnesiothermic reduction with subsequent chemical vapor deposition (CVD) process. Li-ion batteries (LIBs) were fabricated to test the utility of MSNSs as an anode material. LIB anodes based on MSNSs demonstrate a high reversible capacity of 3207 mAh g-1, superior rate performance, and excellent cycling stability. Furthermore, the performance of full cell LIBs was evaluated by using MSNS anode and a LiCoO2 cathode with practical electrode loadings. The MSNS/LiCoO2 full cell demonstrates high gravimetric energy density in the order of 850 Wh L-1 with excellent cycling stability. This work shows a proof of concept of the use of monodisperse Si and C nanocomposite spheres toward practical lithium-ion battery applications.

Towards flexible binderless anodes: silicon/carbon fabrics via double-nozzle electrospinning.

Flexible electrodes (C-Si/C) composed of Si/C fibers trapped in carbon fiber frames via double-nozzle electrospinning improve the cycling stability and rate capability of Si/C fabrics. Polyacrylonitrile (PAN) has been demonstrated as a superior carbon matrix for Si compared with polyvinylpyrrolidone (PVP) annealed using the same heat-treatment process.

Medical expenses in treating acute esophageal variceal bleeding: A 15-year nationwide population-based cohort study.

Acute variceal bleeding in patients with cirrhosis is related to high mortality and medical expenses. The purpose of present studies was to analyze the medical expenses in treating acute esophageal variceal bleeding among patients with cirrhosis and potential influencing clinical factors.A total of 151,863 patients with cirrhosis with International Classification of Diseases-9 codes 456.0 and 456.20 were analyzed from the Taiwan National Health Insurance Research Database from January 1, 1996 to December 31, 2010. Time intervals were divided into three phases for analysis as T1 (1996-2000), T2 (2001-2005), and T3 (2006-2010). The endpoints were prevalence, length of hospital stay, medical expenses, and mortality rate.Our results showed that more patients were <65 years (75.6%) and of male sex (78.5%). Patients were mostly from teaching hospitals (90.8%) with high hospital volume (50.9%) and high doctor service load (51.1%). The prevalence of acute esophageal variceal bleeding and mean length of hospital stay decreased over the years (P < 0.001), but the overall medical expenses increased (P < 0.001). Multiple regression analysis showed that older age, female sex, Charlson comorbidity index (CCI) score >1, patients from teaching hospitals, and medium to high or very high patient numbers were independent factors for longer hospital stay and higher medical expenses. Aged patients, female sex, increased CCI score, and low doctor service volume were independent factors for both in-hospital and 5-year mortality. Patients from teaching hospitals and medium to high or very high service volume hospitals were independent factors for in-hospital mortality, but not 5-year mortality.Medical expenses in treating acute esophageal variceal bleeding increased despite the decreased prevalence rate and length of hospital stay in Taiwan. Aged patients, female sex, patients with increased CCI score from teaching hospitals, and medium to high or very high patient numbers were the independent factors for increased medical expenses.

Template Free and Binderless NiO Nanowire Foam for Li-ion Battery Anodes with Long Cycle Life and Ultrahigh Rate Capability.

Herein, NiO-decorated Ni nanowires with diameters ca. 30-150 nm derived from Ni wire backbone (ca. 2 µm in diameter) is directly synthesized on commercially available Ni foam as a renovated anode for Li-ion batteries. Excellent stability with capacity 680 mAh g(-1) at 0.5C (1C = 718 mA g(-1)) is achieved after 1000 cycles. Superior rate capability is exhibited by cycling at extremely high current rates, such as 20C and 50C with capacities ca. 164 and 75 mAh g(-1), respectively. The capacity can be recovered back to ca. 430 mAh g(-1) in 2 cycles when lowered to 0.2C and stably cycled for 430 times with capacity 460 mAh g(-1). The NiO nanowire foam anode possesses low equivalent series resistance ca. 3.5 Ω, resulting in superior power performance and low resistive losses. The NiO nanowire foam can be manufactured with bio-friendly chemicals and low temperature processes without any templates, binders and conductive additives, which possesses the potential transferring from lab scale to industrial production.

Phase Engineering of 2D Tin Sulfides.

Tin sulfides can exist in a variety of phases and polytypes due to the different oxidation states of Sn. A subset of these phases and polytypes take the form of layered 2D structures that give rise to a wide host of electronic and optical properties. Hence, achieving control over the phase, polytype, and thickness of tin sulfides is necessary to utilize this wide range of properties exhibited by the compound. This study reports on phase-selective growth of both hexagonal tin (IV) sulfide SnS2 and orthorhombic tin (II) sulfide SnS crystals with diameters of over tens of microns on SiO2 substrates through atmospheric pressure vapor-phase method in a conventional horizontal quartz tube furnace with SnO2 and S powders as the source materials. Detailed characterization of each phase of tin sulfide crystals is performed using various microscopy and spectroscopy methods, and the results are corroborated by ab initio density functional theory calculations.

Two step growth phenomena of molybdenum disulfide-tungsten disulfide heterostructures.

Here, we report the first demonstration of atomically thin vertically stacked MoS2/WS2 heterostructures, achieved via a two-step chemical vapour deposition (CVD) growth process. Highly ordered stacking of heterostructure domains and patterned defects have been observed. Computations based on first principles have been performed to understand observed enhanced photoluminescence of the heterostructure.

Oxygen etching of thick MoS2 films.

Oxygen annealing of thick MoS2 films results in randomly oriented and controllable triangular etched shapes, forming pits with uniform etching angles. These etching morphologies differ across the sample based on the defect sites situated on the basal plane surface, forming numerous features in different bulk sample thicknesses.

Scalable synthesis of nano-silicon from beach sand for long cycle life Li-ion batteries.

Herein, porous nano-silicon has been synthesized via a highly scalable heat scavenger-assisted magnesiothermic reduction of beach sand. This environmentally benign, highly abundant, and low cost SiO2 source allows for production of nano-silicon at the industry level with excellent electrochemical performance as an anode material for Li-ion batteries. The addition of NaCl, as an effective heat scavenger for the highly exothermic magnesium reduction process, promotes the formation of an interconnected 3D network of nano-silicon with a thickness of 8-10 nm. Carbon coated nano-silicon electrodes achieve remarkable electrochemical performance with a capacity of 1024 mAhg(-1) at 2 Ag(-1) after 1000 cycles.

Conformational, dynamical. and tensional study of tethered bilayer lipid membranes in coarse-grained molecular simulations.

Tethered bilayer lipid membranes (tBLMs) have attracted great interest recently due to their crucial roles in elucidating fundamental membrane characteristics and the implications in biochemical sensors and pharmaceutical drug carriers. Nevertheless, they have not yet been investigated computationally on the molecular scale. Here, we study tBLMs consisting of DOPCs (1,2-dioleoyl-sn-glycero-3-phosphocholine) as free lipids and pegylated DOPCs (on phosphate group) as tethers in water by a variation of the MARTINI model. By varying grafting densities and tether lengths, distinct conformational changes from planar to undulated bilayers are observed. Lateral diffusivities and lateral pressure profiles show that the dynamical and tensional states are specific to the system configurations. These results suggest that the conformations, fluidity, and elasticity of the tBLMs can be tuned and manipulated to conform to various requirements in theoretical investigations and technological applications.

Deposition of platinum on oxygen plasma treated carbon nanotubes by atomic layer deposition.

Platinum nanoparticles were deposited on oxygen plasma treated carbon nanotubes (CNTs) by atomic layer deposition (ALD). The treatment time with oxygen plasma generated by microwaves under a power of 600 W varied from 5 to 20 s. The number of ALD cycles was controlled at 5-125. X-ray photoelectron spectroscopic analysis indicated that oxygen plasma can graft oxygen-containing functional groups to the CNT surface to act as nucleation sites for growth of Pt nanoparticles. Formation of very uniform and well distributed Pt nanoparticles of a size of 1.60-4.80 nm was achieved. The growth rate of Pt nanoparticles could be controlled by the number of ALD cycles and oxygen plasma treatment time. This offers a dry process to deposit well-dispersed metallic nanoparticles on selected support materials.