High-Rate 4.2 V Solid-State Potassium Batteries by In Situ Polymerized Epoxide Ether Electrolyte

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Solid-state metallic potassium batteries (SSMPBs) show promise as alternatives to lithium-ion batteries.
• Current SSMPBs face challenges with low ionic conductivity and high interfacial resistance, limiting their electrochemical performance.

Purpose of the Study:

• To develop high-rate SSMPBs with improved electrochemical performance.
• To address the limitations of low ionic conductivity and interfacial resistance in existing SSMPB technologies.

Main Methods:

• In situ ring-opening polymerization of 1,3-dioxolane with succinonitrile as a plasticizer and Al(OTf)3 as a catalyst.
• Formation of short-chain polyether electrolytes with enhanced ionic conductivity and stability.
• Electrochemical testing of SSMPBs using the novel electrolytes.

Main Results:

• Achieved high ionic conductivity of 4.5 × 10^-5 S cm^-1 at room temperature.
• Demonstrated excellent stability at high oxidation potentials (4.2 V vs K+/K) and against metallic potassium anodes.
• Obtained a discharge capacity of 69 mAh g^-1 at 100 mA g^-1 with 88.8% retention after 100 cycles.

Conclusions:

• The developed in situ polymerized polyether electrolytes significantly enhance the performance of SSMPBs.
• The new electrolytes offer superior ionic conductivity, stability, and cycling performance compared to previous SSMPB systems.
• This work paves the way for practical applications of high-rate solid-state metallic potassium batteries.