Pacific Northwest National Laboratory

About: Pacific Northwest National Laboratory is a facility organization based out in Richland, Washington, United States. It is known for research contribution in the topics: Catalysis & Aerosol. The organization has 11581 authors who have published 27934 publications receiving 1120489 citations. The organization is also known as: PNL & PNNL.

High Voltage Operation of Ni-Rich NMC Cathodes Enabled by Stable Electrode/Electrolyte Interphases

Abstract: DOI: 10.1002/aenm.201800297 high theoretical specific capacity (3860 mA h g−1), and the lowest negative electrochemical potential (−3.040 V vs the standard hydrogen electrode).[1] Rechargeable Li metal batteries (LMBs), regarded as one of the most promising candidates for next-generation high-energy-density energy storage systems, have been widely investigated since the 1970s.[2] In fact, the Li metal anode (LMA) is indispensable in the research and development of Li–sulfur, Li–air, and solid-state Li batteries.[1,3] Recently, significant progress has been made on high efficiency operation of LMAs, including the modification of electrolyte chemistry,[4,5] use of concentrated electrolytes or additives,[6] selective Li deposition,[2c] application of polymer or solid-state electrolytes,[7] and novel configurations of LMA protection.[2c,8] Recently, a high concentration electrolyte [4 m lithium bis(fluorosulfonyl)imide (LiFSI) in 1,2-dimethoxyethane (DME)] has been reported to enable high rate cycling of Li||Cu cell with a high Coulombic efficiency (CE) of up to 99.1% without dendrite growth.[6b] This was attributed to the preferential decomposition of LiFSI salt that forms a LiF-rich solid electrolyte interphase (SEI) layer, which is beneficial to stabilize the Li metal anode/electrolyte interface, uniform growth of Li films, and suppress the further corrosion of Li metal. In contrast, DME solvent will be decomposed first in a low concentration LiFSI/DME electrolyte and forms a less stable SEI layer dominated by polymeric components. However, ether-based electrolytes are less suitable with the high voltage (>4 V) cathode required for high-energy-density batteries due to their low oxidation potentials. In this regard, carbonate-based electrolytes are a better choice for high-voltage, high-energy-density LMBs. Our recent work on carbonated-based electrolytes revealed that a dual-salt electrolyte of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) and lithium bis(oxalato)borate (LiBOB) in a carbonate solvent mixture with 0.05 m LiPF6 additive can greatly improve the stability of Li metal and suppress Li dendrite formation even at high current densities.[9] However, the energy density of this LMB system is still relatively low owing to the use of LiNi0.4Mn0.4Co0.2O2 (NMC442), which exhibits a limited discharge capacity of ≈160 mA h g−1 at C/10 when charged to 4.3 V, corresponding to a limited energy density of ≈610 W h kg−1. In order to achieve a higher energy density in LMBs, the most effective strategy is to develop cathode The lithium (Li) metal battery (LMB) is one of the most promising candidates for next-generation energy storage systems. However, it is still a significant challenge to operate LMBs with high voltage cathodes under high rate conditions. In this work, an LMB using a nickel-rich layered cathode of LiNi0.76Mn0.14Co0.10O2 (NMC76) and an optimized electrolyte [0.6 m lithium bis(trifluoromethanesulfonyl)imide + 0.4 m lithium bis(oxalato)borate + 0.05 m LiPF6 dissolved in ethylene carbonate and ethyl methyl carbonate (4:6 by weight)] demonstrates excellent stability at a high charge cutoff voltage of 4.5 V. Remarkably, these Li||NMC76 cells can deliver a high discharge capacity of >220 mA h g−1 (846 W h kg−1) and retain more than 80% capacity after 1000 cycles at high charge/discharge current rates of 2C/2C (1C = 200 mA g−1). This excellent electrochemical performance can be attributed to the greatly enhanced structural/interfacial stability of both the Ni-rich NMC76 cathode material and the Li metal anode using the optimized electrolyte.

Review: Some low-frequency electrical methods for subsurface characterization and monitoring in hydrogeology

Abstract: Low-frequency geoelectrical methods include mainly self-potential, resistivity, and induced polarization techniques, which have potential in many environmental and hydrogeological applications. They provide complementary information to each other and to in-situ measurements. The self-potential method is a passive measurement of the electrical response associated with the in-situ generation of electrical current due to the flow of pore water in porous media, a salinity gradient, and/or the concentration of redox-active species. Under some conditions, this method can be used to visualize groundwater flow, to determine permeability, and to detect preferential flow paths. Electrical resistivity is dependent on the water content, the temperature, the salinity of the pore water, and the clay content and mineralogy. Time-lapse resistivity can be used to assess the permeability and dispersivity distributions and to monitor contaminant plumes. Induced polarization characterizes the ability of rocks to reversibly store electrical energy. It can be used to image permeability and to monitor chemistry of the pore water–minerals interface. These geophysical methods, reviewed in this paper, should always be used in concert with additional in-situ measurements (e.g. in-situ pumping tests, chemical measurements of the pore water), for instance through joint inversion schemes, which is an area of fertile on-going research.

Dengue Virus Infection Perturbs Lipid Homeostasis in Infected Mosquito Cells.

Abstract: Dengue virus causes ∼50–100 million infections per year and thus is considered one of the most aggressive arthropod-borne human pathogen worldwide. During its replication, dengue virus induces dramatic alterations in the intracellular membranes of infected cells. This phenomenon is observed both in human and vector-derived cells. Using high-resolution mass spectrometry of mosquito cells, we show that this membrane remodeling is directly linked to a unique lipid repertoire induced by dengue virus infection. Specifically, 15% of the metabolites detected were significantly different between DENV infected and uninfected cells while 85% of the metabolites detected were significantly different in isolated replication complex membranes. Furthermore, we demonstrate that intracellular lipid redistribution induced by the inhibition of fatty acid synthase, the rate-limiting enzyme in lipid biosynthesis, is sufficient for cell survival but is inhibitory to dengue virus replication. Lipids that have the capacity to destabilize and change the curvature of membranes as well as lipids that change the permeability of membranes are enriched in dengue virus infected cells. Several sphingolipids and other bioactive signaling molecules that are involved in controlling membrane fusion, fission, and trafficking as well as molecules that influence cytoskeletal reorganization are also up regulated during dengue infection. These observations shed light on the emerging role of lipids in shaping the membrane and protein environments during viral infections and suggest membrane-organizing principles that may influence virus-induced intracellular membrane architecture.

How much of the world’s land has been urbanized, really? A hierarchical framework for avoiding confusion

Abstract: Urbanization has transformed the world’s landscapes, resulting in a series of ecological and environmental problems. To assess urbanization impacts and improve sustainability, one of the first questions that we must address is: how much of the world’s land has been urbanized? Unfortunately, the estimates of the global urban land reported in the literature vary widely from less than 1–3 % primarily because different definitions of urban land were used. To evade confusion, here we propose a hierarchical framework for representing and communicating the spatial extent of the world’s urbanized land at the global, regional, and more local levels. The hierarchical framework consists of three spatially nested definitions: “urban area” that is delineated by administrative boundaries, “built-up area” that is dominated by artificial surfaces, and “impervious surface area” that is devoid of life. These are really three different measures of urbanization. In 2010, the global urban land was close to 3 %, the global built-up area was about 0.65 %, and the global impervious surface area was merely 0.45 %, of the word’s total land area (excluding Antarctica and Greenland). We argue that this hierarchy of urban land measures, in particular the ratios between them, can also facilitate better understanding the biophysical and socioeconomic processes and impacts of urbanization.