Designing Advanced LiTiXY (X, Y = O, S, Se, and Te) via DFT Engineering: Chalcogen Substitution Incorporation

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Advancing lithium-ion battery (LIB) technologies requires improved cathode materials.
• Key performance metrics include voltage profiles, rate capability, and structural stability.

Purpose of the Study:

• Investigate LiTiXY compounds (X, Y = O, S, Se, Te) using first-principles.
• Analyze the impact of chalcogen substitution on electronic structure, voltage, and transport.
• Develop a model for assessing electrical rate capability.

Main Methods:

• Density Functional Theory (DFT) calculations with GGA and GGA+U.
• Evaluation of band gaps, density of states (DOS), and reaction voltages.
• Application of a novel semi-quantitative model (CCTB) for rate capability analysis.

Main Results:

• LiTiTeS and LiTiSeTe exhibit metallic/near-metallic delithiated states, promoting efficient electron transport.
• Se- and Te-containing systems show moderate volume changes during delithiation, indicating favorable cycling stability.
• Chalcogen substitution significantly influences electronic and structural properties.

Conclusions:

• Targeted anion substitution is a viable strategy for designing high-performance LIB cathodes.
• Understanding electronic structure and structural stability is key to material optimization.
• This research provides a pathway for developing next-generation LIB cathode materials.