Deciphering the Lithium-Ion Conduction Mechanism of LiH in Solid-Electrolyte Interphase

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium hydride (LiH) is a key component of the solid-electrolyte interphase (SEI) in lithium batteries.
• The precise role of LiH in SEI performance remains unclear due to SEI complexity and limited in situ analysis.

Purpose of the Study:

• To elucidate the ion transport properties and electrochemical behavior of LiH within the SEI.
• To provide critical experimental evidence for understanding SEI functionality in lithium batteries.

Main Methods:

• Isotopic exchange and tracer experiments were employed to investigate LiH conductivity.
• In situ transmission electron microscopy (TEM) was used to observe the self-electrochemical decomposition of LiH.

Main Results:

• Superior ionic conductivity and Li+ conduction behavior of LiH in natural SEI were demonstrated.
• The distinct self-electrochemical decomposition of LiH, differing from LiF and Li2O, was visualized.
• Key ion transport mechanisms within the SEI were experimentally evidenced.

Conclusions:

• This work clarifies the critical role of LiH in SEI ion transport and lithium battery performance.
• The findings offer fundamental insights for designing advanced SEI layers and optimizing lithium battery technology.