Revealing cobalt-induced Li-ion trapping at the LATP/LCO interface with a fine-tuned machine learning interatomic...

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Solid-state batteries offer enhanced safety and energy density compared to conventional lithium-ion batteries.
• Interfacial resistance between the solid electrolyte and electrode is a major challenge limiting battery performance.

Purpose of the Study:

• To investigate the atomistic mechanisms of cobalt (Co) migration from LiCoO2 into lithium aluminum titanium phosphate (LATP).
• To understand the impact of Co migration on lithium-ion (Li-ion) transport within the LATP solid electrolyte.
• To provide insights into the origins of interfacial resistance in all-solid-state batteries.

Main Methods:

• Utilized fine-tuned machine learning interatomic potentials for atomistic simulations.
• Performed molecular dynamics simulations to model Co migration and its effects on Li-ion diffusion.
• Analyzed changes in Li-ion transport pathways and local atomic environments.

Main Results:

• Observed Co substitution at titanium (Ti) sites within the LATP structure.
• Demonstrated that Co substitution induces local trapping of Li-ions.
• Revealed disruption of long-range Li-ion diffusion pathways due to Co presence.

Conclusions:

• Co migration significantly impedes Li-ion transport in LATP, contributing to interfacial resistance.
• The findings highlight the critical role of interface stability in all-solid-state battery performance.
• Developed a predictive framework for designing more stable and efficient battery interfaces.