Structural and electronic properties of bulk Li₂O₂: first-principles simulations based on numerical atomic orbitals

Area of Science:

• Materials Science
• Computational Chemistry
• Electrochemistry

Background:

• Advanced materials with high specific energy are crucial for sustainable energy storage, especially in lithium-air batteries.
• Lithium peroxide (Li2O2) is a critical discharge product in non-aqueous lithium-air systems, significantly impacting battery performance.
• Understanding the properties of Li2O2 is essential for improving battery technology.

Purpose of the Study:

• To investigate the atomic and electronic band structure of bulk Li2O2 using density functional theory.
• To compare the performance of different numerical atomic orbital basis sets against plane-wave basis results.
• To develop a localized Wannier basis for modeling electron-vibration interactions and polaron formation in Li2O2.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Analysis of atomic structure, electronic band structure, and Wannier functions.
• Comparison of various basis sets and computational approaches for band gap analysis.

Main Results:

• Detailed analysis of the ionic characteristics and molecular orbital formation in oxygen dimers within Li2O2.
• Identification of band gap discrepancies across different computational methods.
• Development of a localized Wannier basis to model electron-vibration interactions.

Conclusions:

• The study provides a chemically intuitive framework for understanding electron-lattice coupling in Li2O2.
• Findings offer a basis for constructing reduced models to describe polaron dynamics.
• Insights contribute to improving energy storage technologies and materials design for lithium-air batteries.