Influence of Mechanical Fatigue at Different States of Charge on Pouch-Type Li-Ion Batteries.

Since flexible devices are being used in various states of charge (SoCs), it is important to investigate SoCs that are durable against external mechanical deformations. In this study, the effects of a mechanical fatigue test under various initial SoCs of batteries were investigated. More specifically, ultrathin pouch-type Li-ion polymer batteries with different initial SoCs were subjected to repeated torsional stress and then galvanostatically cycled 200 times. The cycle performance of the cells after the mechanical test was compared to investigate the effect of the initial SoCs. Electrochemical impedance spectroscopy was employed to analyze the interfacial resistance changes of the anode and cathode in the cycled cells. When the initial SoC was at 70% before mechanical deformation, both electrodes well maintained their initial state during the mechanical fatigue test and the cell capacity was well retained during the cycling test. This indicates that the cells could well endure mechanical fatigue stress when both electrodes had moderate lithiation states. With initial SoCs at 0% and 100%, the batteries subjected to the mechanical test exhibited relatively drastic capacity fading. This indicates that the cells are vulnerable to mechanical fatigue stress when both electrodes have high lithiation states. Furthermore, it is noted that the stress accumulated inside the batteries caused by mechanical fatigue can act as an accelerated degradation factor during cycling.

Knowledge extraction of sonophotocatalytic treatment for acid blue 113 dye removal by artificial neural networks.

Removing decolorizing acid blue 113 (AB113) dye from textile wastewater is challenging due to its high stability and resistance to removal. In this study, we used an artificial neural network (ANN) model to estimate the effect of five different variables on AB113 dye removal in the sonophotocatalytic process. The five variables considered were reaction time (5-25 min), pH (3-11), ZnO dosage (0.2-1.0 g/L), ultrasonic power (100-300 W/L), and persulphate dosage (0.2-3 mmol/L). The most effective model had a 5-7-1 architecture, with an average deviation of 0.44 and R2 of 0.99. A sensitivity analysis was used to analyze the impact of different process variables on removal efficiency and to identify the most effective variable settings for maximum dye removal. Then, an imaginary sonophotocatalytic system was created to measure the quantitative impact of other process parameters on AB113 dye removal. The optimum process parameters for maximum AB 113 removal were identified as 6.2 pH, 25 min reaction time, 300 W/L ultrasonic power, 1.0 g/L ZnO dosage, and 2.54 mmol/L persulfate dosage. The model created was able to identify trends in dye removal and can contribute to future experiments.

Ultrahigh-rate nickel monosulfide anodes for sodium/potassium-ion storage.

Transition-metal sulfides have been extensively studied as anode materials for use in sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) due to their multi-electron reactions, high rate performance, and abundant available resources. However, the practical capacities of metal sulfides remain low due to conductivity issues, volume expansion, and the use of traditional carbonate electrolytes. To overcome these drawbacks, ether electrolytes can be combined with nanoparticle-based metal sulfide anodes. Herein, a nanoparticle-based nickel monosulfide (NiS) anode with high rate performance in the ether electrolytes of SIBs/PIBs was prepared by heating a mixture of nickel nanoparticles with sulfur. In SIBs, the NiS anode capacity was 286 mA h g-1 at a high current density of 100 A g-1, and excellent cycling performance was observed at 25 A g-1 with a capacity of 468 mA h g-1 after 1000 cycles. Moreover, a full-cell containing a Na3V2(PO4) cathode demonstrated a rate performance of 65 mA h g-1 at a high current density of 100 A g-1. In PIBs, the NiS electrode capacity was 642 and 37 mA h g-1 at 0.5 and 100 A g-1, respectively. Hence, the synthesised NiS nanoparticles possessed excellent storage capability, regardless of the alkali-ion type, suggesting their potential use as robust NiS anodes for advanced battery systems.

Prediction of batch sorption of barium and strontium from saline water.

Celestite and barite formation results in contamination of barium and strontium ions hinder oilfield water purification. Conversion of bio-waste sorbent products deals with a viable, sustainable and clean remediation approach for removing contaminants. Biochar sorbent produced from rice straw was used to remove barium and strontium ions of saline water from petroleum industries. The removal efficiency depends on biochar amount, pH, contact time, temperature, and Ba/Sr concentration ratio. The interactions and effects of these parameters with removal efficiency are multifaceted and nonlinear. We used an artificial neural network (ANN) model to explore the correlation between process variables and sorption responses. The ANN model is more accurate than that of existing kinetic and isotherm equations in assessing barium and strontium removal with adj. R2 values of 0.994 and 0.991, respectively. We developed a standalone user interface to estimate the barium and strontium removal as a function of sorption process parameters. Sensitivity analysis and quantitative estimation were carried out to study individual process variables' impact on removal efficiency.

Lossless Decompression Accelerator for Embedded Processor with GUI.

The development of the mobile industry brings about the demand for high-performance embedded systems in order to meet the requirement of user-centered application. Because of the limitation of memory resource, employing compressed data is efficient for an embedded system. However, the workload for data decompression causes an extreme bottleneck to the embedded processor. One of the ways to alleviate the bottleneck is to integrate a hardware accelerator along with the processor, constructing a system-on-chip (SoC) for the embedded system. In this paper, we propose a lossless decompression accelerator for an embedded processor, which supports LZ77 decompression and static Huffman decoding for an inflate algorithm. The accelerator is implemented on a field programmable gate array (FPGA) to verify the functional suitability and fabricated in a Samsung 65 nm complementary metal oxide semiconductor (CMOS) process. The performance of the accelerator is evaluated by the Canterbury corpus benchmark and achieved throughput up to 20.7 MB/s at 50 MHz system clock frequency.

Binder-free and high-loading sulfurized polyacrylonitrile cathode for lithium/sulfur batteries.

Sulfurized polyacrylonitrile (SPAN) is a promising active material for Li/S batteries owing to its high sulfur utilization and long-term cyclability. However, because SPAN electrodes are synthesized using powder, they require large amounts of electrolyte, conducting agents, and binder, which reduces the practical energy density. Herein, to improve the practical energy density, we fabricated bulk-type SPAN disk cathodes from pressed sulfur and polyacrylonitrile powders using a simple heating process. The SPAN disks could be used directly as cathode materials because their π-π structures provide molecular-level electrical connectivity. In addition, the electrodes had interconnected pores, which improved the mobility of Li+ ions by allowing homogeneous adsorption of the electrolyte. The specific capacity of the optimal electrode was very high (517 mA h gelectrode -1). Furthermore, considering the weights of the anode, separator, cathode, and electrolyte, the Li/S cell exhibited a high practical energy density of 250 W h kg-1. The areal capacity was also high (8.5 mA h cm-2) owing to the high SPAN loading of 16.37 mg cm-2. After the introduction of 10 wt% multi-walled carbon nanotubes as a conducting agent, the SPAN disk electrode exhibited excellent cyclability while maintaining a high energy density. This strategy offers a potential candidate for Li/S batteries with high practical energy densities.

Fabrication of Nickel Sulfide/Nitrogen-Doped Reduced Graphene Oxide Nanocomposite as Anode Material for Lithium-Ion Batteries and Its Electrochemical Performance.

In this study, NiS/graphene nanocomposites were synthesized by simple heat treatment method of three graphene materials (graphene oxide (GO), reduced graphene oxide (rGO) and nitrogen-doped graphene oxide (N-rGO)) and NiS precursor. The morphology and crystal structure of NiS/graphene nanocomposites were characterized using field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Electrochemical properties were also investigated. NiS/graphene nanocomposites homogeneously wrapped by graphene materials have been successfully manufactured. Among the three nanocomposites, NiS/N-rGO nanocomposite exhibited the highest initial and retention capacity in discharge, respectively, of 1240 mAh/g and 467 mAh/g up to 100 cycles at 0.5 C.

Hydrothermal Synthesis and Electrochemical Behavior of the SnO2/rGO as Anode Materials for Lithium-Ion Batteries.

In this work, the hydrothermal method was employed to produce SnO2/rGO as anode material. Nanostructured SnO2 was prepared to enhance reversibility and to deal with the undesirable volume changes during cycling. The SnO2/rGO hybrid exhibits long cycle life in lithium-ion storage capacity and rate capability with an initial discharge capacity of 1327 mAh/g at 0.1 C rate. These results demonstrate that a fabricated SnO2/rGO matrix will be a possible way to obtain high rate performance.

Controlling the Voltage Window for Improved Cycling Performance of SnO2 as Anode Material for Lithium-Ion Batteries.

Transition metal oxide materials with high theoretical capacities have been studied as substitutes for commercial graphite in lithiumion batteries. Among these, SnO2 is a promising alloying reaction-based anode material. However, the problem of rapid capacity fading in SnO2 due to volume variation during the alloying/dealloying processes must be solved. The lithiation of SnO2 results in the formation of a Li2O matrix. Herein, the volume variation of SnO2 was suppressed by controlling the voltage window to 1 V to prevent the delithiation reaction between Li2O and Sn. Using this strategy the unreacted Li2O matrix was enriched with metallic Sn particles, thereby providing a pathway for lithium ions. The specific capacity decay in the voltage window of 0.05-3 V was 1.8% per cycle. However, the specific capacity decay was improved to 0.04% per cycle after the voltage window was restricted (in the range of 0.05-1 V). This strategy resulted in a specific capacity of 374.7 mAh g-1 at 0.1 C after 40 cycles for the SnO2 anode.

Effect of Ordered Carbon Structures on Electrochemical Properties of Carbon/Sulfur Composites in Lithium-Sulfur Batteries.

In this paper, the relationship between the pore spatial structures, pore sizes, and pore types of highly ordered mesoporous CMK-based carbons (CMK-1, CMK-3, and CMK-5) and their electrochemical performance in Li-S batteries is investigated. CMK-1 has a complex spatial structure and small pores. The structure is good for limiting polysulfide in the pores, but not for rapid transfer of Li+ ions in the cell. CMK-3 and CMK-5 have similar spatial structures and pore sizes, but different pore types. Compared to the single pore structure of CMK-3, the bimodal pore structure of CMK-5 not only improves the electrolyte accessibility, but also increases the number of reaction sites, resulting in better electrochemical performance. Studying the correlation between the physical structure of carbon-based materials and their electrochemical performance in Li-S batteries will provide new insights for optimizing porous electrode materials.

Synthesis and Electrochemical Properties of MoS2/rGO/S Composite as a Cathode Material for Lithium-Sulfur Batteries.

To develop the next-generation energy storage systems, lithium-sulfur batteries represent an attractive option due to its high theoretical capacity, and energy density. In this work, MoS2/rGO (reduced graphene oxide) was prepared by hydrothermal synthesis and sulfur added by the melt diffusion method. The as-prepared MoS2/rGO has strong polysulfides entrapping, high conductivity, large surface area, and high catalytic activity, consequently resulting in enhanced rate performance and cycling capability of Li-S batteries. The coin cells were constructed with the MoS2/rGO/S cathode material, exhibit a high reversible capacity of nearly 1380 mAh/g at 0.1 C, outstanding cycling stability with a low capacity fading rate. Present work reveals that the hierarchal MoS2/rGO/S cathodes are potential candidate materials for future high-performance lithium-sulfur batteries.

Free-Standing NiS2 Electrode as High-Rate Anode Material for Sodium-Ion Batteries.

Owing to the speculated price hike and scarcity of lithium resources, sodium-ion batteries are attracting significant research interest these days. However, sodium-ion battery anodes do not deliver good electrochemical performance, particularly rate performance. Herein, we report the facile electrospinning synthesis of a free-standing nickel disulfide (NiS²) embedded on carbon nanofiber. This electrode did not require a conducting agent, current collector, and binder, and typically delivered high capacity and rate performance. The electrode delivered a high initial capacity of 603 mAh g-1 at the current density of 500 mA g-1. Moreover, the electrode delivered the capacity of 271 mAh g-1 at the high current density of 15 A g-1. The excellent rate performance and high coulombic efficiency of the electrode were attributed to its low charge transfer resistance and unique structure.

High power Na3V2(PO4)3 symmetric full cell for sodium-ion batteries.

Sodium-ion batteries (SIBs) are a viable substitute for lithium-ion batteries due to the low cost and wide availability of sodium. However, practical applications require the development of fast charging sodium-ion-based full-cells with high power densities. Na3V2(PO4)3 (NVP) is a bipolar material with excellent characteristics as both a cathode and an anode material in SIBs. Designing symmetric cells with NVP results in a single voltage plateau with significant specific capacity which is ideal for a full cell. Here we demonstrate for the first time a tremendous improvement in the performance of NVP symmetric full cells by introducing an ether-based electrolyte which favors fast reaction kinetics. In a symmetric full cell configuration, 75.5% of the initial capacity was retained even after 4000 cycles at 2 A g-1, revealing ultra-long cyclability. Excellent rate performances were obtained at current densities as high as 1000C, based on the cathode mass, revealing ultrafast Na+ transfer. The power density obtained for this NVP symmetric cell (48 250 W kg-1) is the best among those of all the sodium-ion-based full cells reported to date.

Torsional and Bending Properties of V Taper 2H, ProTaper NEXT, NRT, and One Shape.

Nickel-titanium (NiTi) rotary files have enabled efficient root canal preparations that maintain the canal center with fewer aberrations compared to hand files. However, NiTi rotary files are susceptible to fracture, which can thereby compromise root canal treatment. Therefore, NiTi files have been developed to enhance fracture resistance by modifying design and thermal treatment. The objective of this study was to compare the torsional fatigue resistance and bending resistance of NiTi files manufactured from different alloys and treatments. ProTaper NEXT X2 (PTN; M-wire), V taper 2H (V2H; controlled memory wire), NRT (heat-treated), and One Shape (OS; conventional alloy) instruments of tip size #25 were compared. Torsional fatigue was evaluated by embedding the 3 mm tip of each instrument (N = 10/brand) in resin and the repetitive application of torsional stress (300 rpm, 1.0 N·cm) by an endodontic motor with autostop when the file fractured. The number of loading cycles to fracture was recorded and analyzed by Kruskal-Wallis and Mann-Whitney U tests with Bonferroni's correction. Bending resistance of the instruments was tested using a cantilever bending test to the 3 mm point from the tip (N = 10/brand). The stress was measured when deflection of 3 mm was subjected and statistically analyzed with a one-way analysis of variance and Tukey's honest significance difference test (α = 0.05). V2H withstood the highest number of load applications during torsional fatigue testing (p < 0.05), followed by NRT, PTN, and OS, where the differences between NRT and PTN (p=0.035) and between PTN and OS (p=0.143) were not statistically significant. V2H showed the lowest bending stiffness, followed by NRT, PTN, and OS (p < 0.001). Thermal treatment of NiTi wire resulted in improved mechanical properties, and controlled memory wire provided improved flexibility and torsional fatigue resistance.

Boosting High Energy Density Lithium-Ion Storage via the Rational Design of an FeS-Incorporated Sulfurized Polyacrylonitrile Fiber Hybrid Cathode.

In order to satisfy the escalating energy demands, it is inevitable to improve the energy density of current Li-ion batteries. As the development of high-capacity cathode materials is of paramount significance compared to anode materials, here we have designed for the first time a unique synergistic hybrid cathode material with enhanced specific capacity, incorporating cost-effective iron sulfide (FeS) nanoparticles in a sulfurized polyacrylonitrile (SPAN) nanofiber matrix through a rational in situ synthesis strategy. Previous reports on FeS cathodes are scarce and consist of an amorphous carbon matrix to accommodate the volume changes encountered during the cycling process. However, this inactive buffering matrix eventually increases the weight of the cell, reducing the overall energy density. By the rational design of this hybrid composite cathode, we ensure that the presence of covalently bonded sulfur in SPAN guarantees high sulfur utilization, while effectively buffering the volume changes in FeS. Meanwhile, FeS can compensate for the conductivity issues in the SPAN, thereby realizing a synergistically driven dual-active cathode material improving the overall energy density of the composite. Simultaneous in situ generation of FeS nanoparticles within the SPAN fiber matrix was carried out via electrospinning followed by a one-step heating procedure. The developed hybrid cathode material displays enhanced lithium-ion storage, retaining 688.6 mA h g(FeS@SPAN composite)-1 at the end of 500 cycles at 1 A g-1 even within a narrow voltage range of 1-3.0 V. A high discharge energy density > 900 W h kg(FeS@SPAN composite)-1, much higher than the theoretical energy density of the commercial LiCoO2 cathode, was also achieved, revealing the promising prospects of this hybrid cathode material for high energy density applications.

Effects of the Syzygium aromaticum L. extract on antioxidation and inhibition of matrix metalloproteinase in human dermal fibroblast

Objective: To investigate cosmetic potential of Syzygium aromaticum L. (S. aromaticum L.) and to determine its antioxidant and anti-wrinkling effects. Methods: Using high-performance liquid chromatography, eugenol component was quantitated. The antioxidant activity of S. aromaticum L. was analyzed by 2,2-diphenyl-1-picrylhydrazyl radical scavenging and superoxide dismutase like activities. To determine cell viability, elastase and matrix metalloproteinase-1 (MMP-1) activity, human dermal fibroblasts (HS68) were treated with S. aromaticum L. The inhibitory effect of S. aromaticum L. on tumor necrosis factor alpha induced MMPs expression in HS68 was analyzed by realtime-PCR. Results: The eugenol content was confirmed in S. aromaticum L. S. aromaticum L. was observed to have high 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and superoxide dismutase like activity. S. aromaticum L. had no cytotoxicity against the HS68 and dose-dependently increased elastase inhibition. Moreover, S. aromaticum L. significantly decreased MMP-1 content and inhibited gene levels of MMP-1, MMP-2, MMP-3 and MMP-9. Conclusions: The findings suggest that S. aromaticum L. has great potential as a cosmeceutical ingredient with antioxidant and anti-wrinkling effects.

An Electrospun Core-Shell Nanofiber Web as a High-Performance Cathode for Iron Disulfide-Based Rechargeable Lithium Batteries.

FeS2 /C core-shell nanofiber webs were synthesized for the first time by a unique synthesis strategy that couples electrospinning and carbon coating of the nanofibers with sucrose. The design of the one-dimensional core-shell morphology was found to be greatly beneficial for accommodating the volume changes encountered during cycling, to induce shorter lithium ion diffusion pathways in the electrode, and to prevent sulfur dissolution during cycling. A high discharge capacity of 545 mAh g-1 was retained after 500 cycles at 1 C, exhibiting excellent stable cycling performance with 98.8 % capacity retention at the last cycle. High specific capacities of 854 mAh g-1 , 518 mAh g-1 , and 208 mAh g-1 were obtained at 0.1 C, 1 C, and 10 C rates, respectively, demonstrating the exceptional rate capability of this nanofiber web cathode.

Microstructural Evolution and Electrochemical Properties of HRDSR AZ61-X (X = Ca, Ti) Alloys.

The microstructure and corrosion properties of as-cast AZ61 (Mg-6%Al-1%Zn) and AZ61 alloys doped with titanium and calcium and subjected to high ratio differential speed rolling were investigated. Addition of the alloying elements to the AZ61 alloy resulted in remarkable modification of the morphology and the amount of continuous ß (Mg17Al12)-phase. Addition of Ti to the as-cast AZ61 alloy causes a decrease in the volume fraction (or discontinuity of the ß-phase), leading to strong anodic dissolution. In contrast, addition of Ca to the as-cast AZ61 alloy is rather effective for preventing pitting corrosion. This is attributed to the formation of a semi-continuous network ß-structure. The (Mg, Al)4Ca phases dispersed between the ß (Mg17Al12)-phases led to continuity in the AZ61 alloy with Ca. The AZ61 and AZ61-X(Ca, Ti) alloys subjected to severe plastic deformation via high-ratio differential speed rolling possessed a nano-composite-like microstructure in which the α-Mg matrix with an ultra-fine grain was surrounded by a large number of fine ß particles. These particles were either dynamically precipitated or broken at the grain boundaries, as well as in the grain interiors, by the high ratio differential speed rolling process. The corrosion resistance of the AZ61 and AZ61-X (X = Ca, Ti) alloys subjected to high ratio differential speed rolling was largely improved by the microstructural modification. The high ratio differential speed rolling process greatly influenced the texture of the Mg alloys, which significantly affected their corrosion behavior.

Carbon-Coated Ordered Mesoporous SnO2 Composite Based Anode Material for High Performance Lithium-Ion Batteries.

Recently, tin oxide (SnO2) has received significant attention for use as an anode material for next generation lithium-ion batteries (LIBs) owing to its high theoretical capacity (782 mAh g-1), which is more than twice of that of the commercialized graphite (372 mAh g-1). Several additional advantages, such as low cost, environmental friendliness, easy fabrication and natural abundance improve its promise. Although the theoretical capacity of SnO2 is high, volume expansion during cycling causes issue with cycling stability. In this study, an ordered mesoporous SnO2 was synthesized using a hard template (SBA-15), such that its mesoporous structure can buffer SnO2 particles from cracks caused by volume expansion. It can also allow effective electrolyte infiltration to ensure better reactivity of the active material with Li+ ions. The capacity of synthesized mesoporous SnO2 improved to 218.4 mAh g-1 compared regular SnO2 nanoparticles (69.6 mAh g-1) after 50 cycles at a rate of 0.1 C. Furthermore, carbon-coated mesoporous SnO2 enhanced capacity retention upon cycling (844.6 mAh g-1 after 50 cycles at 0.1 C) by insulating and preventing the cracking of the active material during lithiation and delithiation.

Electrochemical Properties of Micron-Sized SnO Anode Using a Glyme-Based Electrolyte for Sodium-Ion Battery.

Tin monoxide (SnO) anodes are promising candidates for use in sodium-ion batteries because of their high theoretical capacities and stable cycle performance. In previous reports, electrodes with excellent performance have been prepared by using nano-sized SnO particles. However, the synthesis of nano-sized SnO particles is complex, time-consuming, and expensive. In this paper, an anode of micron-sized SnO is prepared by using commercial micron-sized SnO particles. The electrode exhibits a reversible capacity of 450 mAh g-1 in the 1st cycle at a current rate of 100 mA g-1. We used a tetraethylene glycol dimethyl ether (TEGDME)-based electrolyte, which is well known for its superior electrochemical performance in sodium-ion batteries. The mechanism of operation of the anode containing micron-sized SnO particles has been confirmed by a detailed study using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). During initial discharge, the SnO changed to Sn and sodium oxide, and the surface of the electrode became covered with a film. The electrode composed of micron-sized SnO is a potential candidate for use in sodium-ion batteries.