First-Principles Thermodynamics of Hydrogen Absorption in Binary C15 Laves Phases

Area of Science:

• Materials Science
• Physical Chemistry
• Computational Materials Science

Background:

• Intermetallic compounds, particularly AB2 Laves phases with C15 structure, are explored for hydrogen storage.
• Understanding hydrogen absorption thermodynamics is crucial for developing efficient storage materials.

Purpose of the Study:

• To investigate hydrogen absorption thermodynamics in binary C15 Laves phases.
• To determine pressure-composition isotherms for ZrMo2 and ZrV2.
• To identify guidelines for enhancing hydrogen storage capacity in intermetallic compounds.

Main Methods:

• First-principles calculations
• Cluster expansion models
• Statistical mechanics simulations
• High-throughput screening

Main Results:

• ZrMo2 stores hydrogen exclusively in A2B2 tetrahedral sites.
• ZrV2 stores hydrogen in both A2B2 and AB3 tetrahedral sites.
• ZrV2 exhibits higher hydrogen storage capacity than ZrMo2 due to dual-site occupation.
• Identified promising binary C15 Laves phases for multi-site hydrogen accommodation.

Conclusions:

• The type and number of interstitial sites significantly influence hydrogen storage capacity.
• ZrV2's ability to utilize multiple sites enhances its storage potential.
• This research provides chemical design principles for optimizing intermetallic hydrogen storage materials.