Atomically Well-Ordered Structure at Solid Electrolyte and Electrode Interface Reduces the Interfacial Resistance

Area of Science:

• Materials Science
• Electrochemistry
• Surface Science

Background:

• Solid-state batteries offer enhanced safety and energy density compared to conventional lithium-ion batteries.
• The interface between solid electrolytes and electrodes is a critical factor limiting battery performance, particularly ionic conductivity.
• Understanding atomic-level interface structures is crucial for designing high-performance solid-state batteries.

Purpose of the Study:

• To investigate the atomic structures at the interfaces of solid electrolytes (Li3PO4) and electrodes (LiCoO2).
• To correlate interface atomic arrangement with interface resistance in solid-state battery components.
• To elucidate the mechanisms of ion migration influencing interface resistance.

Main Methods:

• Synchrotron surface X-ray diffraction was employed to probe the atomic structures at the solid electrolyte-electrode interfaces.
• Two types of interfaces, exhibiting high and low electrical resistance, were prepared and analyzed.
• Atomic arrangements at the electrode surface and within the interface region were characterized.

Main Results:

• A low-resistance interface was characterized by a flat and well-ordered atomic arrangement at the LiCoO2 electrode surface.
• A high-resistance interface exhibited a disordered atomic structure.
• Lithium ion migration along the interface and into grain/antiphase boundaries was identified as key to reducing interface resistance.

Conclusions:

• The crystallinity and atomic order of the LiCoO2 electrode surface significantly influence interface resistance.
• Optimizing interface structure and promoting Li-ion migration pathways are critical for developing low-resistance solid-state batteries.
• Surface science techniques like X-ray diffraction provide essential insights into interfacial phenomena in energy storage devices.