Optimal hydrogen storage in sodium substituted lithium fullerides

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Fullerides are promising materials for hydrogen storage.
• Tuning the properties of fullerides is crucial for optimizing hydrogen storage capacity and kinetics.

Purpose of the Study:

• To synthesize and characterize novel mixed alkali cluster intercalated fullerides (Na_xLi_6-xC₆₀).
• To investigate the impact of sodium substitution on the hydrogen absorption and desorption properties of Li₆C₆₀.

Main Methods:

• Synthesis of Na_xLi_6-xC₆₀ compounds via substitution of Li with Na in Li₆C₆₀.
• Characterization of crystal structure and lattice parameters.
• Hydrogen absorption/desorption studies using charge/discharge kinetics and calorimetric-manometric evaluation.

Main Results:

• A series of Na_xLi_6-xC₆₀ compounds were successfully synthesized with a cubic parameter linearly dependent on x.
• Optimal hydrogen storage performance was observed for x = 0.5 and x = 1.
• Sodium substitution significantly lowered the hydrogen absorption temperature and improved hydrogenation capacity and kinetics.
• The dehydrogenation enthalpy was found to be 43.8 kJ mol^-1 H₂ for x = 1.

Conclusions:

• Mixed alkali cluster intercalated fullerides offer tunable properties for hydrogen storage.
• Sodium substitution in Li₆C₆₀ enhances its potential for practical hydrogen storage applications.