10Be ages of late Pleistocene deglaciation and Neoglaciation in the north-central Brooks Range, Arctic Alaska

ABSTRACT: We present a chronology of late Pleistocene deglaciation and Neoglaciation for two valleys in the northcentral Brooks Range, Alaska, using cosmogenic 10 Be exposure dating. The two valleys show evidence of ice retreat from the northern range front before $16-15 ka, and into individual cirques by$14 ka. There is no evidence for a standstill or re-advance during the Lateglacial period, indicating that a glacier advance during the Younger Dryas, if any, was less extensive than during the Neoglaciation. The maximum glacier expansion during the Neoglacial is delimited by moraines in two cirques separated by about 200 km and dated to 4.6 AE 0.5 and 2.7 AE 0.2 cal ka BP. Both moraine ages agree with previously published lichen-inferred ages, and confirm that glaciers in the Brooks Range experienced multiple advances of similar magnitude throughout the late Holocene. The similar extent of glaciers during the middle Holocene and the Little Ice Age may imply that the effect of decreasing summer insolation was surpassed by increasing aridity to limit glacier growth as Neoglaciation progressed

The Role of Interlayer Chemistry in Li‐Metal Growth through a Garnet‐Type Solid Electrolyte

Securing the chemical and physical stabilities of electrode/solid-electrolyte interfaces is crucial for the use of solid electrolytes in all-solid-state batteries. Directly probing these interfaces during electrochemical reactions would significantly enrich the mechanistic understanding and inspire potential solutions for their regulation. Herein, the electrochemistry of the lithium/Li7La3Zr2O12-electrolyte interface is elucidated by probing lithium deposition through the electrolyte in an anode-free solid-state battery in real time. Lithium plating is strongly affected by the geometry of the garnet-type Li7La3Zr2O12 (LLZO) surface, where nonuniform/filamentary growth is triggered particularly at morphological defects. More importantly, lithium-growth behavior significantly changes when the LLZO surface is modified with an artificial interlayer to produce regulated lithium depositions. It is shown that lithium-growth kinetics critically depend on the nature of the interlayer species, leading to distinct lithium-deposition morphologies. Subsequently, the dynamic role of the interlayer in battery operation is discussed as a buffer and seed layer for lithium redistribution and precipitation, respectively, in tailoring lithium deposition. These findings broaden the understanding of the electrochemical lithium-plating process at the solid-electrolyte/lithium interface, highlight the importance of exploring various interlayers as a new avenue for regulating the lithium-metal anode, and also offer insight into the nature of lithium growth in anode-free solid-state batteries.

The Role of Interlayer Chemistry in Li-Metal Growth through a Garnet-Type Solid Electrolyte

Securing the chemical and physical stabilities of electrode/solid-electrolyte interfaces is crucial for the use of solid electrolytes in all-solid-state batteries. Directly probing these interfaces during electrochemical reactions would significantly enrich the mechanistic understanding and inspire potential solutions for their regulation. Herein, the electrochemistry of the lithium/Li7La3Zr2O12-electrolyte interface is elucidated by probing lithium deposition through the electrolyte in an anode-free solid-state battery in real time. Lithium plating is strongly affected by the geometry of the garnet-type Li7La3Zr2O12 (LLZO) surface, where nonuniform/filamentary growth is triggered particularly at morphological defects. More importantly, lithium-growth behavior significantly changes when the LLZO surface is modified with an artificial interlayer to produce regulated lithium depositions. It is shown that lithium-growth kinetics critically depend on the nature of the interlayer species, leading to distinct lithium-deposition morphologies. Subsequently, the dynamic role of the interlayer in battery operation is discussed as a buffer and seed layer for lithium redistribution and precipitation, respectively, in tailoring lithium deposition. These findings broaden the understanding of the electrochemical lithium-plating process at the solid-electrolyte/lithium interface, highlight the importance of exploring various interlayers as a new avenue for regulating the lithium-metal anode, and also offer insight into the nature of lithium growth in anode-free solid-state batteries.

Method Using Water-Based Solvent to Prepare Li₇La₃Zr₂O₁₂ Solid Electrolytes

Li-garnet Li₇La₃Zr₂O₁₂ (LLZO) is a promising candidate of solid electrolytes for high-safety solid-state Li⁺ ion batteries. However, because of its high reactivity to water, the preparation of LLZO powders and ceramics is not easy for large-scale amounts. Herein, a method applying water-based solvent is proposed to demonstrate a possible solution. Ta-doped LLZO, that is, Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO), and its LLZTO/MgO composite ceramics are made by attrition milling, followed by a spray-drying process using water-based slurries. The impacts of parameters of the method on the structure and properties of green and sintered pellets are studied. A relative density of ∼95%, a Li-ion conductivity of ∼3.5 × 10^–4 S/cm, and uniform grain size LLZTO/MgO garnet composite ceramics are obtained with an attrition-milled LLZTO/MgO slurry that contains 40 wt % solids and 2 wt % polyvinyl alcohol binder. Li–sulfur batteries based on these ceramics are fabricated and work under 25 °C for 20 cycles with a Coulombic efficiency of 100%. This research demonstrates a promising mass production method for the preparation of Li-garnet ceramics

Colloidal crystal order and structure revealed by tabletop extreme ultraviolet scattering and coherent diffractive imaging

Colloidal crystals with specific electronic, optical, magnetic, vibrational properties, can be rationally designed by controlling fundamental parameters such as chemical composition, scale, periodicity and lattice symmetry. In particular, silica nanospheres -which assemble to form colloidal crystals- are ideal for this purpose, because of the ability to infiltrate their templates with semiconductors or metals. However characterization of these crystals is often limited to techniques such as grazing incidence small-angle scattering that provide only global structural information and also often require synchrotron sources. Here we demonstrate small-angle Bragg scattering from nanostructured materials using a tabletop-scale setup based on high-harmonic generation, to reveal important information about the local order of nanosphere grains, separated by grain boundaries and discontinuities. We also apply full-field quantitative ptychographic imaging to visualize the extended structure of a silica close-packed nanosphere multilayer, with thickness information encoded in the phase. These combined techniques allow us to simultaneously characterize the silica nanospheres size, their symmetry and distribution within single colloidal crystal grains, the local arrangement of nearest-neighbor grains, as well as to quantitatively determine the number of layers within the sample. Key to this advance is the good match between the high harmonic wavelength used (13.5nm) and the high transmission, high scattering efficiency, and low sample damage of the silica colloidal crystal at this wavelength. As a result, the relevant distances in the sample - namely, the interparticle distance (≈124nm) and the colloidal grains local arrangement (≈1μm) - can be investigated with Bragg coherent EUV scatterometry and ptychographic imaging within the same experiment simply by tuning the EUV spot size at the sample plane (5μm and 15μm respectively). In addition, the high spatial coherence of high harmonics light, combined with advances in imaging techniques, makes it possible to image near-periodic structures quantitatively and nondestructively, and enables the observation of the extended order of quasi-periodic colloidal crystals, with a spatial resolution better than 20nm. In the future, by harnessing the high time-resolution of tabletop high harmonics, this technique can be extended to dynamically image the three-dimensional electronic, magnetic, and transport properties of functional nanosystems