Solid electrolyte interphase formation between the Li_0.29La_0.57TiO₃ solid-state electrolyte and a Li-metal anode: an...

Area of Science:

• Solid-state electrochemistry
• Materials science
• Computational chemistry

Background:

• Solid-state electrolytes are crucial for next-generation batteries.
• Understanding electrolyte-anode interfaces is key to battery stability.
• Lithium-metal anodes offer high energy density but face stability challenges.

Purpose of the Study:

• To investigate the formation and evolution of the interface between Li$_{0.29}$La$_{0.57}$TiO$_{3}$ solid-state electrolyte and Li-metal anode.
• To analyze the impact of external electric fields on interphase stability.
• To elucidate the chemical and structural changes at the electrochemical interface.

Main Methods:

• Ab initio molecular dynamics simulations.
• Application of external electric fields (0, 0.5, 1.0, 2.0 V Å^-1).
• Analysis of Bader charge variation and atomic diffusion.

Main Results:

• Lithium-oxide (Li$_{2}$O) and lanthanum-oxide (La$_{2}$O$_{3}$) phases form at the interface.
• Increased electric fields promote oxygen diffusion from the electrolyte into the Li-metal anode.
• Titanium (Ti) reduction and Li-metal anode amorphization are observed.
• Anode structure transitions from BCC to amorphized near Li-oxide phases.

Conclusions:

• The electrolyte/anode interface is unstable due to continuous oxide formation and growth.
• Interface instability is exacerbated by increasing external electric fields.
• The findings provide insights into degradation mechanisms in solid-state batteries.