High-loading LiBH₄ Confined in Structurally Tunable Ni Catalyst-decorated Porous Carbon Scaffold for Fast Hydrogen...

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Lithium borohydride (LiBH4) exhibits poor hydrogen desorption kinetics and reversibility, limiting its application in hydrogen storage.
• High LiBH4 loading typically reduces hydrogen storage performance due to mass transfer limitations.

Purpose of the Study:

• To develop a nanoconfined LiBH4 system with improved hydrogen storage performance at high loadings.
• To leverage catalyst/nanoconfinement synergy for enhanced dehydrogenation kinetics and reversibility.

Main Methods:

• Synthesis of a porous carbon-sphere scaffold decorated with Ni nanoparticles (NPs) from a Ni metal-organic framework precursor.
• Partial etching of Ni NPs to create a high surface area, porous structure accommodating high LiBH4 loading (up to 60 wt.%).
• Evaluation of hydrogen storage performance, including dehydrogenation kinetics, capacity, and reversibility.

Main Results:

• The optimized scaffold successfully accommodated 60 wt.% LiBH4, demonstrating significant catalyst/nanoconfinement synergy.
• Enhanced dehydrogenation kinetics were observed, with >87% of hydrogen capacity released within 30 min at 375°C.
• Apparent activation energies were reduced from 149.6 kJ/mol for pure LiBH4 to 110.5 and 98.3 kJ/mol for the confined system.
• Partial reversibility was achieved under moderate conditions (75 bar H2, 300°C) with rapid dehydrogenation during cycling.

Conclusions:

• The Ni-catalyzed nanoconfined LiBH4 system overcomes the limitations of high loading and sluggish kinetics.
• This approach offers a promising strategy for developing advanced materials for efficient hydrogen storage.