Quantifying Hydrogen Chemical Diffusivity in NdNiO₃ Thin Films through Operando Multimodal Measurements

Area of Science:

• Materials Science
• Solid-State Chemistry
• Oxide Electronics

Background:

• Nickelate oxides possess unique properties for electrocatalysis, neuromorphic computing, and superconductors.
• Proton insertion is key to tuning these properties, but its dynamics are poorly understood.
• Accurate quantification of hydrogen chemical diffusivity in nickelates is a significant knowledge gap.

Purpose of the Study:

• To develop and apply a novel quantitative approach for measuring hydrogen chemical diffusivity in nickelate oxides.
• To precisely determine hydrogen chemical diffusivity in NdNiO3 (NNO), a representative nickelate.
• To address discrepancies and lack of rigorous methods in previous studies.

Main Methods:

• Utilized *operando* multimodal measurements for real-time analysis.
• Employed rigorous kinetic modeling for data interpretation.
• Performed cross-validation across multiple data dimensions for accuracy.

Main Results:

• Successfully quantified hydrogen chemical diffusivity in NdNiO3.
• Revealed inherently limited proton mobility in NNO.
• Challenged the prevailing assumption of rapid proton transport in nickelates.

Conclusions:

• The precise quantification of hydrogen diffusivity provides critical data for optimizing proton-based devices.
• Findings necessitate a re-evaluation of ion dynamics in correlated oxides.
• This work establishes a robust methodology for future studies on ion transport in materials.