Deciphering the liquid-solid interactions in dealkalization of O3 layered oxides
Wujiu Zhang1, Jifu Zhu1, Amin Song1
1State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, China.
Nature Communications
|March 20, 2026
Summary
Residual alkali in O3-phase layered oxides hinders battery applications. Ethylene glycol effectively removes alkali without causing structural damage, unlike water, offering a stable dealkalization method for advanced battery materials.
Area of Science:
- Materials Science
- Electrochemistry
- Solid-State Chemistry
Background:
- O3-phase layered oxides are key positive electrode materials for advanced batteries, offering structural stability and tunability.
- Surface residual alkali is a major challenge for their large-scale application, especially in sodium-based systems.
- Conventional water washing for alkali removal causes lattice collapse and ion leaching in sodium-based materials.
Purpose of the Study:
- To elucidate the interaction mechanism between solid-phase electrode materials and liquid-phase solvents during dealkalization.
- To understand how solvent molecular configuration and alkali metal-oxygen bond covalency influence structural degradation.
- To develop a theoretical framework for assessing the stability of O3-phase layered oxides against liquid-phase treatments.
Main Methods:
- Investigated the dealkalization mechanism using water (H2O/H3O+) and ethylene glycol as model solvents.
- Analyzed the role of solvent molecular structure and alkali metal-oxygen bond covalency in structural stability.
- Established a time-dependent deterioration framework for evaluating material stability against liquid phases.
Main Results:
- Water (H2O/H3O+) causes self-propagating intercalation and protonation, leading to sodium ion leakage and lattice destabilization.
- Ethylene glycol, due to its molecular size, effectively removes alkali without inducing significant structural degradation.
- A framework for predicting material stability based on solvent interaction and material properties was developed.
Conclusions:
- The molecular configuration of solvents critically determines the structural integrity of O3-phase layered oxides during dealkalization.
- Ethylene glycol presents a viable alternative to water for alkali removal, preserving the structural integrity of sodium-based materials.
- This research provides crucial theoretical insights for designing effective liquid-phase engineering strategies for advanced battery materials.
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