Søren Strandskov Sørensen

The practical strength of oxide glasses is greatly reduced by surface flaws that form during processing and use. Instrumented indentation can mimic such real‐life damage events and allows for systematic examination of the deformation and structural changes in the regions of the glass being indented. However, structural probing is nearly always performed after rather than during the sharp contact event, limiting our understanding of the indentation process. To overcome this, here we develop and apply an in situ nanofocus X‑ray scattering method for visualizing and quantifying indentation‐induced densification and cracking in glass materials. We demonstrate its feasibility in a proof‐of‐concept experiment by probing the local mechanical and structural response of vitreous silica during indentation. Two‐dimensional mapping of the scattering pattern in the zone below a sharp diamond wedge indenter reveals local changes in the atomic structure and density as well as cracking behavior. These in situ measurements during indentation reveal the formation and evolution of the densification zone and cracking, probing features down to the nanoscale. Although the developed experimental approach can be further improved (especially beam‐sample‐indenter alignment), we believe it will allow for a deeper understanding of the interplay between structural densification and cracking behavior in glasses.

Disordered materials such as glasses are promising candidates as solid-state electrolytes for batteries, but they tend to exhibit low ionic conductivity and current methods for investigating and predicting the ionic conductivity of electrolyte materials are inefficient. Here, we propose a framework that summarizes the topological properties of the electrolyte material’s atomic structure with a weighted graph based on periodic boundary conditions. We then compute a variation of the max-flow algorithm, a commonly used model in continuum models of transportation and liquid flow, on this summary and show that it is compatible with the simulated periodic atomic structures. Using molecular dynamics simulations of various glassy solid-state electrolyte families including both mobile lithium and sodium ions, we validate the approach by showing a positive correlation between the area-normalized maximum flow predicted from the static glass structures and the ionic conductivity as obtained from the simulations, especially in the case of high-conductivity sulfide glass electrolytes. We envision that the developed methodology, which only relies on static atomic structure, will accelerate the discovery of highly conductive sulfide glassy electrolytes for high-performance all-solid-state batteries.

Small alcohol molecules can tune how hybrid coordination network glasses melt and form by loosening Co–O connections. Changing the size and amount of alcohol lowers melting and glass transition temperatures by making the network more flexible.

Metal‐organic framework (MOF) glasses represent a promising class of organic‐inorganic hybrid materials, but most crystalline MOFs undergo thermal decomposition before melting and can thus not be quenched into a glassy state. To this end, recent work has introduced the concept of MOF modifiers, i.e., the mixing of a modifier agent with a MOF crystal to lower the MOF's melting temperature. While previous work has focused on hybrid modifiers, we here investigate the use of inorganic ammonium halide salts as modifiers for zeolitic imidazolate frameworks (ZIFs). We show that co‐melting various ZIF crystals with the halide salt significantly lowers both melting and glass transition temperatures, enabling fabrication of centimeter‐sized hybrid glasses and melt‐processing of ZIF‐8, which otherwise decomposes before melting. In situ X‑ray imaging is used to visualize that the molten halide salts infiltrate the ZIF crystals and ultimately promote the collapse of the crystalline domains into a homogeneous melt. X‐ray pair distribution function analyses confirm the disruption of the Zn─N coordination network and formation of Zn─X (X = Cl, Br, and I) bonding, thus lowering the framework connectivity. Our findings broaden the scope of modified MOF glasses and offer a versatile route for tailoring their thermal processing and network structure.

The structural role of alkali modifiers (Li, Na, and K) in aluminoborosilicate glasses remains incompletely understood despite their widespread industrial use. Here, we investigate a series of glasses with compositions 20M₂O-xB₂O₃-(20-x)Al₂O₃-60SiO₂ (M = Li, Na, K; x = 5, 10, 15, with additional x = 0 and 20 for Na). Lithium-containing samples are prepared in duplicate using isotope-enriched compositions to enable isotopic-difference neutron diffraction. Solid-state NMR shows that ∼98% of Al is tetrahedrally coordinated, independent of alkali type, while the fraction of tetrahedral B increases with decreasing alkali-field strength and increasing B/Al ratio. Neutron total scattering data are analyzed by peak fitting of real-space correlation functions, using NMR-derived coordination numbers as constraints. Subtle variations in B-O, Si-O, and Al-O bond lengths are observed, and by the isotopic difference method, we find that the Li-O bonds exhibit an asymmetric bond length distribution and an increasing coordination number with increasing B/Al ratio. A similar trend is observed for the Na-O bonds, exploiting the improper difference method. These results provide new insight into how alkali modifiers influence the structure of aluminoborosilicate glasses, which will be helpful for establishing composition-structure-property relations.

The transition to clean energy and sustainable technologies necessitates securing strategic materials, yet traditional land-based mining is increasingly unsustainable. Seawater holds immense potential as a mineral source, but its intricate ionic composition limits current extraction techniques. Here, we report a family of ion-exchangeable materials by grafting phosphate groups onto metal-organic framework glasses, followed by precise heat and aqueous treatments. This process introduces facile exchangeable ions and exposes active functional groups. The developed materials display progressively enhanced Mg²⁺/Ca²⁺ selectivity as solution complexity increases from binary and ternary mixtures to synthetic seawater. Across three different natural seawater samples, the optimized material achieves Mg²⁺ uptake of 7-10 mg g^-1 and Li⁺ uptake of 2-3 mg g^-1 within 10 min, highlighting high capacity and rapid kinetics under realistic conditions. Quantitative mechanistic analysis reveals that ion exchange contributes to 72% of the total uptake, while 28% arises from phosphate functional groups and pore surface interactions. This dual-mode sorption mechanism underpins the material's excellent selectivity and rate performance relative to a typical commercial resin. Our work thus presents a promising route for designing efficient adsorbents to extract valuable minerals from unconventional sources and help to secure the raw materials vital for a low-carbon future.

The transition to clean energy and sustainable technologies necessitates securing precious metals, yet traditional land-based mining is increasingly unsustainable. Seawater holds immense potential as a mineral source, but its intricate ionic composition limits current extraction techniques. Here, we report a family of ion-exchangeable materials by grafting phosphate groups onto metal-organic framework glasses, followed by precise heat and aqueous treatments. This process introduces facile exchangeable ions and exposes active functional groups. Based on these structural features, the materials exhibit superior performance in selective recovery of magnesium and lithium from various natural seawater samples, surpassing a typical commercial resin in uptake rate, capacity, and recyclability. Our work presents a promising route for designing efficient adsorbents to extract valuable minerals from unconventional sources and help to secure the raw materials vital for a low-carbon future.