High capacity group-IV elements (Si, Ge, Sn) based anodes for lithium-ion batteries

AbstractTremendous efforts have been devoted to replace commercial graphite anode (372 mAh g−1) by group IV elements (Si, Ge, Sn) based-materials with high capacities in lithium-ion batteries (LIBs). The use of these materials is hampered by the pulverization of these particles due to the high volumetric change during lithiation and delithiation cycles, which leads to particles pulverization and destabilization of solid electrolyte interphase (SEI) films. These problems result in fast capacity fading and low Coulombic efficiency. Nanostructured materials show significant improvements in rate capability and cyclability due to their high surface-to-volume ratio, reduced Li+ diffusion length, and increased freedom associated with the volume change during cycling. However, the nanostructured active materials with high ratio of surface-to-volume increase the irreversible capacity due to the formation of more SEI films. Although the nanostructured materials active materials keep relatively stable during repeated cycles of lithiation/delithiation process, the SEI film continually breaks/reforms, lowing the Coulombic efficiency. Meanwhile, the high-cost, low Coulombic efficiency and low tapping density limit the commercialization of the nanostructured electrode materials. Therefore, it is urgent to find solutions which could take advantage of both long cycle life of nanomaterials within the group IV elements (Si, Ge, Sn) and high volumetric/gravimetric capacity of micro-materials in the group IV as well as elements (Si, Ge, Sn). This report presents an overview of the recently developed strategies for improving the group IV elements (Si, Ge, Sn)-based anodes performances in LIBs to provide a further insight understanding in designing novel anodes

Analysis and Estimation of the Maximum Switch Current during Battery System Reconfiguration

Batteries are interconnected in series and/or parallel to meet wide-range power or energy demands in various industrial applications. To pursue the benefits of multiple connection structures in one system, reconfigurable battery systems (RBSs) have recently emerged for safe and efficient operation, extended energy storage and delivery, etc. Switches are the essential elements to enable the battery system reconfiguration, but selecting appropriate switches for RBS designs has not been systematically investigated. To bridge this gap, analytical expressions are derived in this paper to estimate the maximum switch current and its upper limit to facilitate the selection of RBS switches. An RBS prototype based on H-bridges is set up and experimental results verify the effectiveness and advantage of the proposed estimation method. These analytical expressions, relying only on resistances of batteries and switches, are readily applicable to practical RBS design and much more efficient than conducting numerous circuit experiments, simulation tests, or circuit analyses, especially for large-scale systems. Moreover, the analysis framework and estimation method proposed for series-parallel mutual conversion can be adaptively extended to other complex system reconfigurations to facilitate various RBS designs

Microstructure, mechanical properties and machinability of particulate reinforced Al matrix composites: a comparative study between SiC particles and high-entropy alloy particles

In this study, 2024Al matrix composites reinforced by SiC particles (SiC-2024Al) and nanocrystalline high-entropy alloy particles (HEA-2024Al) fabricated by powder metallurgy were systematically compared for the first time. There is a significant difference in microstructure and mechanical properties as well as machinability between two kinds of composites. In term of microstructure, when the volume fraction of reinforcements was 10%, both SiC-2024Al and HEA-2024Al composites showed a homogeneous particle distribution in the matrix. With the increase of reinforcement content, HEA-2024Al composites presented denser microstructure than that of SiC-2024Al composites. The composites with 10, 20 and 30 vol.% HEA reinforcements all showed better plasticity than that of the SiC-2024Al composites with same volume fraction of reinforcements, which was related with better particle distribution and interface bonding. However, the strength showed the opposite tendency in the two kinds of composites. Selecting 10SiC-2024Al and 10HEA-2024Al composites as examples to explore the difference in the yield strength of two kinds of composites, it is ascribed to the dislocation punched zones around interface between the Al matrix and reinforcements, which was analyzed in detail by a combination of calculation, nanoindentation tests and finite element analysis. Additionally, HEA-2024Al composites showed better machinability than those of SiC-2024Al composites. This work provides insight into the application of particulate reinforced Al matrix composites

Temperature dependence of erythromelalgia mutation L858F in sodium channel Nav1.7

BACKGROUND: The disabling chronic pain syndrome erythromelalgia (also termed erythermalgia) is characterized by attacks of burning pain in the extremities induced by warmth. Pharmacological treatment is often ineffective, but the pain can be alleviated by cooling of the limbs. Inherited erythromelalgia has recently been linked to mutations in the gene SCN9A, which encodes the voltage-gated sodium channel Nav1.7. Nav1.7 is preferentially expressed in most nociceptive DRG neurons and in sympathetic ganglion neurons. It has recently been shown that several disease-causing erythromelalgia mutations alter channel-gating behavior in a manner that increases DRG neuron excitability. RESULTS: Here we tested the effects of temperature on gating properties of wild type Nav1.7 and mutant L858F channels. Whole-cell voltage-clamp measurements on wild type or L858F channels expressed in HEK293 cells revealed that cooling decreases current density, slows deactivation and increases ramp currents for both mutant and wild type channels. However, cooling differentially shifts the midpoint of steady-state activation in a depolarizing direction for L858F but not for wild type channels. CONCLUSION: The cooling-dependent shift of the activation midpoint of L858F to more positive potentials brings the threshold of activation of the mutant channels closer to that of wild type Nav1.7 at lower temperatures, and is likely to contribute to the alleviation of painful symptoms upon cooling in affected limbs in patients with this erythromelalgia mutation

Interfacial electronic structure at the CH3NH3PbI3/MoOx interface

Interfacial electronic properties of the CH3NH3PbI3 (MAPbI3)/MoOx interface are investigated using ultraviolet photoemission spectroscopy and X-ray photoemission spectroscopy. It is found that the pristine MAPbI3 film coated onto the substrate of poly (3,4-ethylenedioxythiophene) poly(styrenesulfonate)/indium tin oxide by two-step method behaves as an n-type semiconductor, with a band gap of ~1.7 eV and a valence band edge of 1.40 eV below the Fermi energy (EF). With the MoOx deposition of 64A ° upon MAPbI3, the energy levels of MAPbI3 shift toward higher binding energy by 0.25 eV due to electron transfer from MAPbI3 to MoOx. Its conduction band edge is observed to almost pin to the EF, indicating a significant enhancement of conductivity. Meanwhile, the energy levels of MoOx shift toward lower binding energy by ~0.30 eV, and an interface dipole of 2.13 eV is observed at the interface of MAPbI3/MoOx. Most importantly, the chemical reaction taking place at this interface results in unfavorable interface energy level alignment for hole extraction. A potential barrier of ~1.36 eV observed for hole transport will impede the hole extraction from MAPbI3 to MoOx. On the other hand, a potential barrier of ~0.14 eV for electron extraction is too small to efficiently suppress electrons extracted from MAPbI3 to MoOx. Therefore, such an interface is not an ideal choice for hole extraction in organic photovoltaic devices

Quality Difference between Aged Brine Marinated andQuantitative Marinated Beef

This study aimed to analyze the quality differences of sauced beef with aged brine and quantitative marinating methods by evaluating sensory characteristics, color, shear force, texture, moisture distribution, taste nucleotides, and free amino acids. Results showed that quantitative marinated beef received a higher score in sensory evaluation than aged brine marinated beef. Additionally, quantitative marinated beef had better color, lower shear force and hardness compared to aged brine marinated beef (P<0.05). It also had a higher moisture content and more even moisture distribution. The quantitative marinating method resulted in higher levels of 5′-AMP, 5′-IMP, and 5′-GMP in the beef sauce, which enhanced its umami intensity (P<0.05). Moreover, the total free amino acid content was higher in quantitative marinated beef (475.60 mg/100 g) than aged brine marinated beef (274.66 mg/100 g). These findings suggested that the use of quantitative marinating method can significantly improve the quality of marinated beef products and promote the industry's advancement

Perceptions of malaria control and prevention in an era of climate change: a cross-sectional survey among CDC staff in China

Published online: 31 March 2017Background: Though there was the significant decrease in the incidence of malaria in central and southwest China during the 1980s and 1990s, there has been a re-emergence of malaria since 2000. Methods: A cross-sectional survey was conducted amongst the staff of eleven Centers for Disease Control and Prevention (CDC) in China to gauge their perceptions regarding the impacts of climate change on malaria transmission and its control and prevention. Descriptive analysis was performed to study CDC staff’s knowledge, attitudes, perceptions and suggestions for malaria control in the face of climate change. Results: A majority (79.8%) of CDC staff were concerned about climate change and 79.7% believed the weather was becoming warmer. Most participants (90.3%) indicated climate change had a negative effect on population health, 92.6 and 86.8% considered that increasing temperatures and precipitation would influence the transmission of vector-borne diseases including malaria. About half (50.9%) of the surveyed staff indicated malaria had re-emerged in recent years, and some outbreaks were occurring in new geographic areas. The main reasons for such re-emergence were perceived to be: mosquitoes in high-density, numerous imported cases, climate change, poor environmental conditions, internal migrant populations, and lack of health awareness. Conclusions: This study found most CDC staff endorsed the statement that climate change had a negative impact on infectious disease transmission. Malaria had re-emerged in some areas of China, and most of the staff believed that this can be managed. However, high densities of mosquitoes and the continuous increase in imported cases of malaria in local areas, together with environmental changes are bringing about critical challenges to malaria control in China. This study contributes to an understanding of climate change related perceptions of malaria control and prevention amongst CDC staff. It may help to formulate in-house training guidelines, community health promotion programmes and policies to improve the capacity of malaria control and prevention in the face of climate change in China.Michael Xiaoliang Tong, Alana Hansen, Scott Hanson, Easey, Scott Cameron, Jianjun Xiang, Qiyong Liu, Xiaobo Liu, Yehuan Sun, Philip Weinstein, Gil, Soo Han, Craig Williams and Peng B

Integrated Assessment of Heavy Metal Contamination in Sediments from a Coastal Industrial Basin, NE China

The purpose of this study is to investigate the current status of metal pollution of the sediments from urban-stream, estuary and Jinzhou Bay of the coastal industrial city, NE China. Forty surface sediment samples from river, estuary and bay and one sediment core from Jinzhou bay were collected and analyzed for heavy metal concentrations of Cu, Zn, Pb, Cd, Ni and Mn. The data reveals that there was a remarkable change in the contents of heavy metals among the sampling sediments, and all the mean values of heavy metal concentration were higher than the national guideline values of marine sediment quality of China (GB 18668-2002). This is one of the most polluted of the world’s impacted coastal systems. Both the correlation analyses and geostatistical analyses showed that Cu, Zn, Pb and Cd have a very similar spatial pattern and come from the industrial activities, and the concentration of Mn mainly caused by natural factors. The estuary is the most polluted area with extremely high potential ecological risk; however the contamination decreased with distance seaward of the river estuary. This study clearly highlights the urgent need to make great efforts to control the industrial emission and the exceptionally severe heavy metal pollution in the coastal area, and the immediate measures should be carried out to minimize the rate of contamination, and extent of future pollution problems

Genome-Wide Analysis of DNA Methylation and Cigarette Smoking in a Chinese Population

Background: Smoking is a risk factor for many human diseases. DNA methylation has been related to smoking, but genome-wide methylation data for smoking in Chinese populations is limited. Objectives: We aimed to investigate epigenome-wide methylation in relation to smoking in a Chinese population. Methods: We measured the methylation levels at > 485,000 CpG sites (CpGs) in DNA from leukocytes using a methylation array and conducted a genome-wide meta-analysis of DNA methylation and smoking in a total of 596 Chinese participants. We further evaluated the associations of smoking-related CpGs with internal polycyclic aromatic hydrocarbon (PAH) biomarkers and their correlations with the expression of corresponding genes. Results: We identified 318 CpGs whose methylation levels were associated with smoking at a genome-wide significance level (false discovery rate < 0.05), among which 161 CpGs annotated to 123 genes were not associated with smoking in recent studies of Europeans and African Americans. Of these smoking-related CpGs, methylation levels at 80 CpGs showed significant correlations with the expression of corresponding genes (including RUNX3, IL6R, PTAFR, ANKRD11, CEP135 and CDH23), and methylation at 15 CpGs was significantly associated with urinary 2-hydroxynaphthalene, the most representative internal monohydroxy-PAH biomarker for smoking. Conclusion: We identified DNA methylation markers associated with smoking in a Chinese population, including some markers that were also correlated with gene expression. Exposure to naphthalene, a byproduct of tobacco smoke, may contribute to smoking-related methylation. Citation: Zhu X, Li J, Deng S, Yu K, Liu X, Deng Q, Sun H, Zhang X, He M, Guo H, Chen W, Yuan J, Zhang B, Kuang D, He X, Bai Y, Han X, Liu B, Li X, Yang L, Jiang H, Zhang Y, Hu J, Cheng L, Luo X, Mei W, Zhou Z, Sun S, Zhang L, Liu C, Guo Y, Zhang Z, Hu FB, Liang L, Wu T. 2016. Genome-wide analysis of DNA methylation and cigarette smoking in Chinese. Environ Health Perspect 124:966–973; http://dx.doi.org/10.1289/ehp.150983