Dynamic Regulation Achieving High-Performance La-Containing Prussian Blue Analogues for Aqueous K⁺ Storage.

Area of Science:

• Materials Science
• Electrochemistry
• Inorganic Chemistry

Background:

• Lanthanum (La) enhances material performance but La-containing Prussian blue analogues (PBAs) suffer from poor aqueous stability.
• Dissolution of La-PBAs in aqueous electrolytes limits their use as potassium-ion (K+) storage hosts.

Purpose of the Study:

• To develop a dynamic regulating strategy to overcome the high solubility of La-containing PBAs.
• To achieve high structural stability and superior aqueous K+ storage using La-containing PBAs.

Main Methods:

• Chemical component regulation: Fe3+ ions fill La3+ vacancies, modifying the surface to prevent La dissolution.
• Structural regulation: Transformation from hexagonal to cubic lattice during cycling for optimal structure.
• Electrochemical characterization and density functional theory (DFT) for mechanism elucidation.

Main Results:

• The modified surface effectively hinders La atom dissolution.
• Improved electron/ion transfer and increased K+ storage capacity due to remaining La atoms.
• Ultrahigh capacities achieved: 171 mAh g-1 at 1 A g-1, stable over 1000 cycles.

Conclusions:

• A novel dynamic regulating strategy successfully enhances the stability and K+ storage performance of La-containing PBAs in aqueous electrolytes.
• The developed La-containing PBAs demonstrate significant potential as advanced cathode materials for aqueous energy storage devices.