Glass in Two Forms: Heterogeneous Electrical Relaxation in Nanoglassy Petalite

Abstract

Glassy materials with specific functions are almost universally used in our daily life. If prepared via quenching, that is, by rapid cooling of the molten glass, a frozen liquid with a high degree of lattice disorder and stress is obtained. The release of stress through mechanical action may significantly affect the microstructure and dynamic features of the so-obtained nanoglass. Considering ion conducting glasses, it has recently been shown that mechanical treatment of glasses causes the long-range ion transport to significantly decrease. The origin of this astonishing behavior of nanoglasses is, however, far from being understood completely. Here, we show that depending on the duration of mechanical impact in a high-energy planetary ball mill, the petalite glass, LiAlSi4O10, passes through a state with two Li reservoirs distinctly differing in electrical relaxation and, thus, in ion transport. The two species, characterized by electrical relaxation rates differing by two orders of magnitude, show up clearly if we use the electric modulus representation to analyze the data. This feature is also seen in conductivity spectra revealing a two-step increase of the conductivity with frequency. Accordingly, we propose a two-phase model with nanometer-sized non-relaxed glassy particles next to or surrounded by structurally relaxed regions.

Ionic Conductivity of Nanocrystalline and Amorphous Li10GeP2S12: The Detrimental Impact of Local Disorder on Ion Transport

“…Under the conditions of soft mechanical treatment we suppose that a core-shell structure is generated with the amorphous phase covering the (nano-)crystalline LGPS regions. This picture resembles that of nanocrystalline alumosilicates and nanoglasses obtained after mechanical treatment 61 .…”

Understanding the Origin of Enhanced Li-Ion Transport in Nanocrystalline Argyrodite-Type Li6PS5I

“…73,77 For Li 6 PS 5 I, we expect that, besides the effect of interfacial regions, defect-rich bulk regions of the nmsized crystallites will also substantially contribute to long-range ionic conduction. The latter effect has been observed for LiTaO 3 , 73,98 whose ionic conductivity can be increased by 6 orders of magnitude if mechanically treated for several hours in planetary mills.…”

Fast Li Ion Dynamics in the Mechanosynthesized Nanostructured Form of the Solid Electrolyte Li3YBr6

“…Interestingly, ionic transport in nanocrystalline LYB does not exceed that of its crystalline counterpart. Many other examples have been presented in the literature showing that poor (oxide, fluoride, and even sulfide) conductors can be converted into materials with enhanced ionic conductivity. − These enhancements were usually attributed to defects introduced during ball milling; furthermore, ion transport in nanocrystalline materials may benefit from interfacial ion dynamics and space charge regions , providing sources for facile ion transport. Here, the crystalline structure of LYB is slightly superior to the nanocrystalline form revealing that the above-mentioned O–T–O migration pathway governs bulk ion transport rather than interfacial effects.…”