Highly concentrated electrolyte solutions for 4 V class potassium-ion batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Potassium-ion batteries (KIBs) are promising for large-scale energy storage.
• Developing stable and efficient electrolytes is crucial for advancing KIB technology.
• Current electrolytes often face limitations in voltage stability and cycling performance.

Purpose of the Study:

• To demonstrate stable cycling of a 4 V-class potassium-ion battery.
• To investigate the performance of a highly concentrated electrolyte based on potassium bis(fluorosulfonyl)amide in 1,2-dimethoxyethane.
• To compare the performance of this novel electrolyte against conventional potassium hexafluorophosphate/carbonate ester solutions.

Main Methods:

• Fabrication and testing of graphite//K2Mn[Fe(CN)6] half cells and full cells.
• Electrolyte preparation using a highly concentrated potassium bis(fluorosulfonyl)amide in 1,2-dimethoxyethane solution.
• Electrochemical cycling and performance evaluation (coulombic efficiency, cyclability).

Main Results:

• The highly concentrated electrolyte enabled stable cycling of 4 V-class potassium-ion batteries.
• Graphite and K2Mn[Fe(CN)6] half cells using this electrolyte showed enhanced performance.
• Graphite//K2Mn[Fe(CN)6] full cells demonstrated superior coulombic efficiency and cyclability compared to KPF6/carbonate ester electrolytes.

Conclusions:

• Highly concentrated potassium bis(fluorosulfonyl)amide in 1,2-dimethoxyethane is a viable electrolyte for stable 4 V-class potassium-ion batteries.
• This electrolyte offers significant advantages over conventional systems for both half and full cell applications.
• The findings pave the way for developing high-performance and durable potassium-ion batteries.