Spray‐coated Hard Carbon Composite Anodes for Sodium‐Ion Insertion

Sodium-ion batteries are among the most promising alternatives to lithium-ion batteries. Hard carbon (HC) electrodes have been recognized as suitable active anode material for mono-valent ion batteries. Here, we present a simple and cost-effective spray-coating process to prepare HC composite electrodes on copper current collectors with different binder (sodium carboxymethyl cellulose, CMC) content and different HC particle sizes. The spray-coated electrodes were evaluated and tested in 1 M sodium perchlorate (NaClO$_4$) in propylene carbonate (PC) in dependence of the CMC content with and without fluoroethylene carbonate (FEC) as additive, and the performance was also compared to doctor bladed HC electrodes. Spray-coated anodes in Na half-cells revealed improved capacity during the first cycles compared with doctor bladed anodes with similar thicknesses. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) studies were performed, which revealed a significant increase of inorganic fluoro-compounds in the formed solid electrolyte interphase (SEI) when FEC was present as additive. In addition, first single electrode microcalorimetry studies on spray-coated thin HC composite electrodes yielded an entropy of the sodiation process of 80 J mol$^{−1}$ K$^{−1}$ at high state of charge (SoC), comparable to that of bulk Na deposition

Microscopic and Spectroscopic Analysis of the Solid Electrolyte Interphase at Hard Carbon Composite Anodes in 1 M NaPF6_6 /Diglyme

The formation of the solid electrolyte interphase (SEI) on HC composite electrodes plays a crucial role in enhancing the performance and operational stability of sodium (Na$^+$) ion batteries. It has been demonstrated that for HC anodes improved electrochemical performance, e. g., increase in coulombic efficiency (CE) and improved rate performance have been achieved in ether-based electrolytes. Here, we investigate spray-coated HC composite electrodes charged at low and high current rates in 1 M sodium hexafluorophosphate (NaPF$_6$) in diglyme using half-cell experiments. The pristine and cycled HC anodes were examined in terms of conductivity and their electrochemical properties after cycling. In 1 M NaPF$_6$ ether-based electrolyte, the spray-coated HC composite electrodes (film thickness approx. 22.0 μm with an active mass loading of approx. 2.0 mg cm$^{−2}$) reached a discharge capacity of 431 mA h g$^{−1}$ at 0.1 C that stays constant for 40 cycles, which is substantially higher than that obtained in carbonate-based electrolytes. We investigated the formed interphase using conductive atomic force microscopy (c-AFM), scanning electrochemical microscopy (SECM), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary-ion mass spectrometry (ToF-SIMS), revealing distinct differences for longer cycling and at varying current rates which indicates that the properties of the formed SEI layers are influenced by the formation conditions

Proteomic responses to ocean acidification of the marine diazotroph Trichodesmium under iron-replete and iron-limited conditions

Abstract(#br)Growth and dinitrogen (N 2 ) fixation of the globally important diazotrophic cyanobacteria Trichodesmium are often limited by iron (Fe) availability in surface seawaters. To systematically examine the combined effects of Fe limitation and ocean acidification (OA), T. erythraeum strain IMS101 was acclimated to both Fe-replete and Fe-limited concentrations under ambient and acidified conditions. Proteomic analysis showed that OA affected a wider range of proteins under Fe-limited conditions compared to Fe-replete conditions. OA also led to an intensification of Fe deficiency in key cellular processes (e.g., photosystem I and chlorophyll a synthesis) in already Fe-limited T. erythraeum . This is a result of reallocating Fe from these processes to Fe-rich nitrogenase to..

Gross and net production during the spring bloom along the Western Antarctic Peninsula

Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of New Phytologist Trust for personal use, not for redistribution. The definitive version was published in New Phytologist 205 (2015): 182-191, doi:10.1111/nph.13125.This study explores some of the physiological mechanisms responsible for high productivity near the shelf in the Western Antarctic Peninsula despite a short growing season and cold temperature. We measured gross and net primary production at Palmer Station during the summer 2012/2013 via three different techniques: 1) incubation with H218O; 2) incubation with 14CO2; and 3) in situ measurements of O2/Ar and triple oxygen isotope. Additional laboratory experiments were performed with the psychrophilic diatom Fragilariopsis cylindrus. During the spring bloom, which accounted for more than half of the seasonal gross production at Palmer Station, the ratio of net to gross production reached a maximum greater than ~60%, among the highest ever reported. The use of multiple-techniques showed that these high ratios resulted from low heterotrophic respiration and very low daylight autotrophic respiration. Laboratory experiments revealed a similar ratio of net to gross O2 production in F.cylindrus and provided the first experimental evidence for an important level of cyclic electron flow (CEF) in this organism. The low ratio of community respiration to gross primary production observed during the bloom at Palmer Station may be characteristic of high latitude coastal ecosystems and partially supported by a very active CEF in psychrophilic phytoplankton.This study was supported by funds from the US National Science Foundation (Award numbers 1040965 and 1043593). Funding to PDT was provided by the Natural Science and Engineering Research Council of Canada

Reduced nitrogenase efficiency dominates response of the globally important nitrogen fixer Trichodesmium to ocean acidification

工业革命以来，海洋吸收了约三分之一人为排放的CO2，以迄今3亿年来最快的速度酸化（CO2升高、pH下降），这势必影响海洋生态系统的关键过程和功能。研究团队创新性地从区分海洋酸化过程中CO2上升和pH下降的双重效应入手，揭示了海水CO2升高的正效应小于pH下降的负效应，故酸化的净效应为抑制束毛藻的固氮作用。这是因为酸化引起束毛藻胞质 pH下降，从而降低固氮酶效率、干扰胞内pH稳态、影响细胞产能。在上述研究工作的基础上，进一步系统地测定了固氮和光合系统蛋白的表达量及其含铁量，建立了一个束毛藻的“资源最优化分配”细胞模型。实现了实验数据和数值模型的紧密结合：实验数据是构筑模型的坚实基础，并提高了模型的预测水平；通过模型模拟，加深了对实验发现的认知，并对实验结论进行了时空拓展。 罗亚威博士和史大林博士为论文的共同第一作者和共同通讯作者，史大林课题组的洪海征教授、研究助理沈容和博士生张福婷为共同作者。论文的共同作者还包括美国佛罗里达州立大学助理教授Sven Kranz博士和乔治亚大学副教授Brian Hopkinson博士。【Abstract】The response of the prominent marine dinitrogen (N2)-fixing cyanobacteria Trichodesmium to ocean acidification (OA) is critical to understanding future oceanic biogeochemical cycles. Recent studies have reported conflicting findings on the effect of OA on growth and N2 fixation of Trichodesmium. Here, we quantitatively analyzed experimental data on how Trichodesmium reallocated intracellular iron and energy among key cellular processes in response to OA, and integrated the findings to construct an optimality-based cellular model. The model results indicate that Trichodesmium growth rate decreases under OA primarily due to reduced nitrogenase efficiency. The downregulation of the carbon dioxide (CO2)-concentrating mechanism under OA has little impact on Trichodesmium, and the energy demand of anti-stress responses to OA has a moderate negative effect. We predict that if anthropogenic CO2 emissions continue to rise, OA could reduce global N2 fixation potential of Trichodesmium by 27% in this century, with the largest decrease in iron-limiting regions.This work was funded by the National Key R&D Program of China (2016YFA0601404 and 2016YFA0601203), NSFC (41476093, 41721005, 41890802, 31861143022 and 41376116), and the MEL internal research fund (MELRI1502).本项研究得到了国家重点研发计划（2016YFA0601404 和2016YFA0601203）以及国家自然科学基金系列项目（41476093, 41721005, 41890802, 31861143022 和41376116）的资助

Metabolic balance of coastal Antarctic waters revealed by autonomous pCO2 and ΔO2/Ar measurements

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 41 (2014): 6803–6810, doi:10.1002/2014GL061266.We use autonomous gas measurements to examine the metabolic balance (photosynthesis minus respiration) of coastal Antarctic waters during the spring/summer growth season. Our observations capture the development of a massive phytoplankton bloom and reveal striking variability in pCO2 and biological oxygen saturation (ΔO2/Ar) resulting from large shifts in community metabolism on time scales ranging from hours to weeks. Diel oscillations in surface gases are used to derive a high-resolution time series of net community production (NCP) that is consistent with 14C-based primary productivity estimates and with the observed seasonal evolution of phytoplankton biomass. A combination of physical mixing, grazing, and light availability appears to drive variability in coastal Antarctic NCP, leading to strong shifts between net autotrophy and heterotrophy on various time scales. Our approach provides insight into the metabolic responses of polar ocean ecosystems to environmental forcing and could be employed to autonomously detect climate-dependent changes in marine primary productivity.This study was supported by funds from the U.S. National Science Foundation (OPP awards ANT-0823101, ANT-1043559, ANT-1043593, and ANT-1043532) as well as support for PDT and ECA from the National Science and Engineering Research Council of Canada.2015-04-0

Structural characteristics and contractual terms of specialist palliative homecare in Germany

Background Multi-professional specialist palliative homecare (SPHC) teams care for palliative patients with complex symptoms. In Germany, the SPHC directive regulates care provision, but model contracts for each federal state are heterogeneous regarding staff requirements, cooperation with other healthcare providers, and financial reimbursement. The structural characteristics of SPHC teams also vary. Aim We provide a structured overview of the existing model contracts, as well as a nationwide assessment of SPHC teams and their structural characteristics. Furthermore, we explore whether these characteristics serve to find specifc patterns of SPHC team models, based on empirical data. Methods This study is part of the multi-methods research project “SAVOIR”, funded by the German Innovations Fund. Most model contracts are publicly available. Structural characteristics (e.g. number, professions, and affiliations of team members, and external cooperation) were assessed via an online database (“Wegweiser Hospiz- und Palliativversorgung”) based on voluntary information obtained from SPHC teams. All the data were updated by phone during the assessment process. Data were descriptively analysed regarding staff, cooperation requirements, and reimbursement schemes, while latent class analysis (LCA) was used to identify structural team models. Results Model contracts have heterogeneous contract partners and terms related to staff requirements (number and qualifications) and cooperation with other services. Fourteen reimbursement schemes were available, all combining different payment models. Of the 283 SPHC teams, 196 provided structural characteristics. Teams reported between one and 298 members (mean: 30.3, median: 18), mainly nurses and physicians, while 37.8% had a psychosocial professional as a team member. Most teams were composed of nurses and physicians employed in different settings; for example, staff was employed by the team, in private practices/nursing services, or in hospitals. Latent class analysis identified four structural team models, based on the team size, team members’ affiliation, and care organisation. Conclusion Both the contractual terms and teams’ structural characteristics vary substantially, and this must be considered when analysing patient data from SPHC. The identified patterns of team models can form a starting point from which to analyse different forms of care provision and their impact on care quality