Microstructural Characterization of Dehydrogenated Products of the LiBH₄-YH₃ Composite

Abstract

The dehydrogenated microstructure of the lithium borohydride-yttrium hydride (LiBH4-YH3) composite obtained at 350°C under 0.3 MPa of hydrogen and static vacuum was investigated by transmission electron microscopy combined with a focused ion beam technique. The dehydrogenation reaction between LiBH4 and YH3 into LiH and YB4 takes place under 0.3 MPa of hydrogen, which produces YB4 nano-crystallites that are uniformly distributed in the LiH matrix. This microstructural feature seems to be beneficial for rehydrogenation of the dehydrogenation products. On the other hand, the dehydrogenation process is incomplete under static vacuum, leading to the unreacted microstructure, where YH3 and YH2 crystallites are embedded in LiBH4 matrix. High resolution imaging confirmed the presence of crystalline B resulting from the self-decomposition of LiBH4. However, Li2B12H12, which is assumed to be present in the LiBH4 matrix, was not clearly observed.

Complex and liquid hydrides for energy storage

“…These mostly amorphous higher borane byproducts are quite stable thermodynamically, and they seem to be more difficult to rehydrogenate than the competing metal borides. Another issue is the influence of the hydrogen back/partial pressure on the formation of the dodecaboranes instead of metal borides [231][232][233]. When the dehydrogenation reaction occurs below a critical hydrogen partial pressure at a given temperature, it tends to form dodecaborane, which seems not to readily react with the metal hydrides to form metal borides.…”

Imaging and Analysis of Encapsulated Objects through Self‐Assembled Electron and Optically Transparent Graphene Oxide Membranes

“…We first tested nanoparticle opals [30] as a model of a solid undeformable object for the encapsulation [31] . A diluted solution of polystyrene nanoparticles (1 μm in diameter) was drop cast and dried on a cover glass pre-coated with Au film (Figure 3a).…”

“…Graphene oxide encapsulation of immiscible liquids on a solid substrate represents another interesting class of practically important deformable objects [31] demonstrating very different results as compared to encapsulated solid objects. As a model system, we used mercury that has poor wettability to most interfaces due to its high surface tension, leading to the well-known challenges in collecting toxic Hg spills.…”

“…Figure 9a shows an STEM image of E. coli bacteria on a 50 nm thick polyimide TEM grid encapsulated by graphene oxide (right panel) and uncovered (left panel). The central image comprises both encapsulated and non-encapsulated regions [31] . Figure 9d exemplifies our approach to fix and image a grass pollen in STEM mode.…”