Record-high room-temperature K⁺ ionic conductivity in anion-deficient pyrochlore

Area of Science:

• Solid-state chemistry
• Materials science
• Electrochemistry

Background:

• Potassium-ion batteries require efficient solid electrolytes for enhanced performance and safety.
• Developing novel materials with high ionic conductivity is crucial for advancing battery technology.

Purpose of the Study:

• To investigate the potential of KAl$_{0.33}$W$_{1.67}$O$_{6}$ defect pyrochlore as a solid electrolyte.
• To achieve and report record potassium ion conductivity for solid electrolytes.

Main Methods:

• Spark plasma sintering was employed to fabricate KAl$_{0.33}$W$_{1.67}$O$_{6}$ defect pyrochlore pellets.
• Ionic conductivity measurements were performed at room temperature.

Main Results:

• The synthesized KAl$_{0.33}$W$_{1.67}$O$_{6}$ defect pyrochlore exhibited an average total K$^{+}$ conductivity of 1.1 × 10$^{-3}$ S cm$^{-1}$ at room temperature.
• This conductivity represents a record value for known potassium ionic conductors.

Conclusions:

• Defect pyrochlores show significant potential as solid electrolytes for potassium-ion batteries.
• The high ionic conductivity of KAl$_{0.33}$W$_{1.67}$O$_{6}$ makes it a promising candidate for next-generation energy storage.