In this article, we investigate the mixed alkaline-earth effect in a silicate glass series with varying the molar ratio of [MgO]/([CaO]+ [MgO]). This effect manifests itself as a minimum in Vickers microhardness (H V ), coefficient of thermal expansion (CTE), and isokom temperatures at 10 12 (T g ) and 10 2 PaÁs, and as a maximum in liquid fragility. To probe the structural origin of the mixed alkaline-earth effect in CTE and H v , we conducted the Raman measurements. In contrast to the aluminosilicate glasses, the present glass series exhibit a negative deviation of shift of peak position at~1100 cm À1 from a linear additivity, indicating the role of the aluminum speciation in affecting the vibration modes. By fitting the Vogel-Fulcher-Tamann equation to the high-temperature viscosity data, we found a near-linear increase of the fractional free volume with the gradual substitution of Ca by Mg, confirming the dynamic structural mismatch model describing the mixed modifier effect. This work gives insight into the mixed modifier effect in glassy systems. K E Y W O R D Sglass, hardness, mixed modifier effect, structure, viscosity

We investigate the thermal and electrochemical properties of xFe2O3‐(100‐x) P2O5 glass (x = 20, 30, 40, and 50 mol%) and 50Fe2O3‐50P2O5 (50FeP) glass‐ceramics as anodes for lithium‐ion batteries (LiBs). The results show that both the glass transition temperature and the energy bandgap monotonically decrease with the increasing Fe2O3 while a critical Fe2O3 content of 30 mol% is found to give glass the highest thermal stability, the largest capacity at 1 Ag‐1, and the lowest charge‐transfer resistance before cycling. Moreover, Fe3(P2O7)2 crystals formed during heat treatment in 50FeP glass effectively enhances the electrochemical properties. The optimum heat treatment condition for 50FeP glass is found at 1033 K for 4 h, that is, 1033 K‐4 h sample enables a reversible capacity of 237 mA h g−1 at the end of 1000 cycles at 1 Ag‐1, which is more than 1.5 times higher than that of the 50FeP glass‐based anode. These findings suggest that the Fe2O3‐P2O5 glass‐ceramics hold significant potential for the effective development of new types of glass anodes for future advanced LiBs.

Owing to heterogeneous nucleation at the melt‐crucible interface, it is difficult to access the dynamic and physical properties of supercooled liquids of poor glass formers when using a conventional melting technique. To avoid the interface nucleation, we apply a containerless aerodynamic levitation laser‐melting technique to measure the viscosity, density, and surface tension of a poor glass‐forming system, ie, the mixed alkaline‐earth aluminate melts. The temperature and composition (Ca/Sr) dependence of thermal‐physical properties are investigated on both thermodynamically stable and metastable supercooled melts. In addition, the levitation laser‐melting technique is used to quench the melts to glasses, and then the mixed alkaline‐earth effects are investigated on Vickers micro‐hardness and glass transition temperatures. By comparing the chosen silicate and aluminate series, we have identified weaker mixed alkaline‐earth effects in aluminate series than those in silicate series, and this difference could be attributed to the different structural roles of alkaline‐earth elements in two glass series.

High hardness and high crack resistance are usually mutually exclusive in glass materials. Through the aerodynamic levitation and laser melting technique, we prepared a series of magnesium aluminosilicate glasses with a constant MgO content, and found a striking enhancement of both hardness and crack resistance with increasing Al2O3. The crack resistance of the magnesium aluminosilicate glass is about five times higher than that of the binary alumina‐silica glass for the similar [Al]/([Al] + [Si]) molar ratio (around 0.6). For the selected magnesium aluminosilicate glass with R = 0.32, when subjected to isothermal treatment at 1283K, we observed a further drastic enhancement of both hardness and crack resistance by extending the heating time. Based on the structural analyses, we propose an atomic‐scale model to explain the mechanism of synergetic enhancement in hardness and crack resistance for the magnesium aluminosilicate glasses and glass‐ceramics.