Controlling the Decomposition Pathway of LiBH₄ via Confinement in Highly Ordered Nanoporous Carbon

Abstract

The wetting and decomposition behavior of LiBH 4 has been investigated in the presence of highly ordered nanoporous hard carbon (NPC) with hexagonally packed 2 nm diameter columnar pores. Calorimetry, X-ray diffraction, and IR spectroscopy measurements confirm that the LiBH 4 within the pores is amorphous. The confinement of LiBH 4 in such small pores results in the disappearance of the low-temperature structural phase transition, the melting transition, and also the significant decrease of the onset desorption temperature from 460 to 220 °C with respect to bulk LiBH 4 , a lower temperature than observed in larger pore sizes in the literature. Most importantly, our results suggest that diborane release is suppressed or eliminated in the decomposition of noncrystalline LiBH 4 . Tight nanoconfinement may therefore mitigate both safety concerns and loss of active material in borohydride-based hydrogen storage systems.

Dehydriding Property of NaBH₄ Combined with Mg₂FeH₆

“…20) Similarly, in xNaBH 4 + (1 ¹ x)Mg 2 FeH 6 , the refined lattice parameter of Mg 2 FeH 6 was found to slightly change, for example, from 0.64436(5) nm of pure Mg 2 FeH 6 to 0.64497(11) nm in NaBH 4 + Mg 2 FeH 6 (x = 0.5) although 6 , further investigation such as solid state nuclear magnetic resonance and infrared spectroscopy will be used to study the hydrogen bonding state. In situ high resolution synchrotron-XRD measurements will be used to obtain more detailed structural data.…”

Recent Progress in Metal Borohydrides for Hydrogen Storage

“…It was first applied in the NH 3 BH 3 system [211] and good improvement was obtained: The dehydrogenation temperature was largely decreased and the amount of borazine gas (an impurity) was significantly reduced. Recently, this approach was introduced for M(BH 4 ) n materials, and some recent achievements [160,[212][213][214][215][216][217][218][219][220][221][222] are summarized in Table 6.…”

Dehydriding Process and Hydrogen–Deuterium Exchange of LiBH4–Mg2FeD6 Composites

“…The main issues to be resolved for developing LiBH4 as a hydrogen storage material are lowering of its high dehydriding temperature of >420 °C and moderating the harsh rehydriding conditions of 35 MPa H2 and high temperatures above 600 °C [2]. Many attempts have been made to improve the dehydriding properties of LiBH4 by incorporating various additives, confining within nanoporous materials, or by preparing reactive composites with metal hydrides, and so on [3][4][5][6][7][8][9][10][11][12].…”