A highly concentrated electrolyte for high-efficiency potassium metal batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Potassium-ion batteries (KIBs) are promising for grid-scale energy storage.
• Developing stable and high-performance K anodes is crucial for KIB advancement.
• Highly concentrated electrolytes offer potential for improved battery stability.

Purpose of the Study:

• To report a novel, highly concentrated electrolyte for potassium-ion batteries.
• To investigate the electrochemical performance of potassium metal anodes in this electrolyte.
• To evaluate the cycling stability and capacity retention of K||potassium Prussian blue (KPB) batteries.

Main Methods:

• Preparation of a 4 M potassium bis(fluorosulfonyl)imide (KFSI) electrolyte in diethylene glycol dimethyl ether (DEGDME).
• Electrochemical cycling of K metal anodes against KPB cathodes.
• Long-term cycling performance testing to assess capacity retention and Coulombic efficiency.

Main Results:

• The 4 M KFSI in DEGDME electrolyte demonstrated stable cycling of K metal anodes.
• High Coulombic efficiency (CE) exceeding 98% over 400 cycles was achieved.
• Excellent capacity retention of 99.7% after 500 cycles was observed for K||KPB batteries.

Conclusions:

• Highly concentrated electrolytes can enable stable cycling of potassium metal anodes.
• The developed KFSI-based electrolyte shows significant potential for high-performance potassium-ion batteries.
• This work contributes to the development of next-generation energy storage solutions.