10 Search Results

Aqueous rechargeable sodium-ion batteries (ARNIBs) are emerging as cost-effective and safe candidates for large-scale energy storage applications. However, their advancement has been constrained by the narrow electrochemical stability window (ESW) of conventional aqueous electrolytes (1.23 V). Here, in this study, we present a transformative approach using an inexpensive and rapidly dissolvable inorganic glass material, water glass (W-glass), to significantly enhance the ESW and enable the development of solid-state, self-supporting aqueous film (SSA film) electrolytes. These SSA film electrolytes exhibit an extended ESW of up to 3.5 V and a conductivity of ∼10^–4 S/cm at room temperature. Structural analysis using magic-anglemore » spinning nuclear magnetic resonance (NMR) and solution-state NMR reveals that the dissolution of W-glass in water is driven by the interdependent hydrolysis of P–O–P linkages and Na⁺–H⁺ ion exchange. This work offers a cost-effective and scalable solution for advancing high-performance ARNIB technology, addressing critical barriers to commercial adoption.« less

When subjected to irradiation or vitrification, minerals become disordered at the atomic scale, which, in turn, affect their density and stiffness. However, the nature of the relationship between structural disorder, density, and stiffness remains poorly understood. In this work, based on molecular dynamics simulations, we investigate the effect of irradiation- and vitrification-induced disordering in a series of silicate minerals. We show that irradiation- and vitrification-induced disordering yield comparable, yet not fully equivalent variations in density and stiffness. Interestingly, we report the existence of a power law density–stiffness scaling exhibiting a scaling exponent that is similar to that observed in porousmore » assembled cellular materials.« less

We report that when exposed to high-energy radiations, the silicate aggregates used in concrete can exhibit some swelling. This, in turn, can result in some internal stress, which can lead to micro-cracks or de-bonding along the cement–aggregate interface. However, there is presently some uncertainty regarding the long-term effect of such high-energy irradiation on aggregates and the associated risk of cracking and failure. Here, based on atomistic simulations, we investigate the effect of neutron irradiation on eight silicate minerals belonging to three different mineralogical families. We demonstrate that the irradiation-induced alterations do not depend on the silicate family but rather onmore » the inherent structure and composition of each mineral. Interestingly, we show that vitrification can be used as a surrogate to assess the upper limit of irradiation-induced swelling. Further, we observe that this swelling potentially leads to high internal stresses, which can result in the initiation and propagation of cracks. Lastly, these findings can guide the selection of optimal aggregate minerals for which the risk of concrete failure upon irradiation is minimized.« less

Water, under conditions of nanoscale confinement, exhibits anomalous dynamics, and enhanced thermal deformations, which may be further enhanced when such water is in contact with hydrophilic surfaces. Such heightened thermal deformations of water could control the volume stability of hydrated materials containing nanoconfined structural water. Understanding and predicting the thermal deformation coefficient (TDC, often referred to as the CTE, coefficient of thermal expansion), which represents volume changes induced in materials under conditions of changing temperature, is of critical importance for hydrated solids including: hydrogels, biological tissues, and calcium silicate hydrates, as changes in their volume can result in stress development,more » and cracking. By pioneering atomistic simulations, we examine the physical origin of thermal expansion in calcium-silicate-hydrates (C–S–H), the binding agent in concrete that is formed by the reaction of cement with water. We report that the TDC of C–S–H shows a sudden increase when the CaO/SiO₂ (molar ratio; abbreviated as Ca/Si) exceeds 1.5. This anomalous behavior arises from a notable increase in the confinement of water contained in the C–S–H’s nanostructure. We identify that confinement is dictated by the topology of the C–S–H’s atomic network. Altogether, the results suggest that thermal deformations of hydrated silicates can be altered by inducing compositional changes, which in turn alter the atomic topology and the resultant volume stability of the solids.« less

Irradiation and vitrification can both result in the disordering of minerals. However, it remains unclear whether these effects are comparable or if the glassy state represents an upper limit for irradiation-induced disordering. By reactive molecular dynamics simulations, we compare the structure of irradiated quartz to that of glassy silica. We show that although they share some degree of similarity, the structure of irradiated quartz and glassy silica differs from each other, both at the short- (<3 Å) and the medium-range (>3 Å and <10 Å). In particular, the atomic network of irradiated quartz is found to comprise coordination defects, edge-sharingmore » units, and large rings, which are absent from glassy silica. These results highlight the different nature of irradiation- and vitrification-induced disordering.« less