Tracing the ionic evolution during ILG induced phase transformation in strontium cobaltite thin films

Area of Science:

• Materials Science
• Solid-State Chemistry
• Electrochemistry

Background:

• Ionic liquid gating (ILG) is a novel materials design approach.
• ILG facilitates ion incorporation/extraction from crystal lattices, yielding new properties.
• The underlying mechanisms of ion and charge transport in ILG remain largely unexplored.

Purpose of the Study:

• To investigate the mechanisms of ionic diffusion and electronic transport during ILG.
• To elucidate the role of collaborative charge and ion transport in phase transformations.
• To understand the electric-field control of ion incorporation and extraction in complex oxides.

Main Methods:

• Utilized brownmillerite SrCoO2.5 as a model system.
• Employed electric-field controlled gating to induce tri-state phase transformations (SrCoO2.5, HSrCoO2.5, SrCoO3-δ).
• Investigated ionic diffusion and electronic transport processes through controlled gating experiments.

Main Results:

• Demonstrated a collaborative interaction between charge transport and ion diffusion is crucial for phase formation.
• Showed that proximity to the electrode influences electron shuttling, ion incorporation, and phase transformation.
• Observed successive phase development across the thin film as the reaction front moves away from the electrode.

Conclusions:

• Unveiled the fundamental mechanism of electric-field-controlled ionic incorporation and extraction.
• Provided insights into the interplay between electronic and ionic transport in complex oxides.
• Established a strategy for designing material functionalities through controlled ionic gating.