Core shell structure for solid gas synthesis of LiBD(4).

Area of Science:

• Materials Science
• Inorganic Chemistry
• Solid-State Chemistry

Background:

• Lithium borohydride (LiBH4) is a promising material for hydrogen storage.
• Understanding the synthesis pathways and limitations of LiBH4 formation is crucial for its practical application.

Purpose of the Study:

• To investigate the formation mechanism of LiBH4 from LiD in a diborane/hydrogen atmosphere.
• To analyze the factors limiting the reaction yield and product microstructure.

Main Methods:

• In situ neutron diffraction to monitor LiBH4 nucleation and growth.
• Microstructural analysis using electron microscopy.
• Chemical analysis employing electron energy loss spectrometry.

Main Results:

• LiBH4 nucleation begins at 100°C in its orthorhombic phase.
• The reaction remains incomplete, with yields around 50% at 185°C.
• A core-shell structure was observed, with LiBH4 forming a passivation layer on LiD grains.

Conclusions:

• The formation of LiBH4 from LiD is limited by the development of a passivating surface layer.
• Optimizing reaction conditions or alternative synthesis strategies are needed to improve LiBH4 yield.