A Nonaqueous Potassium-Based Battery-Supercapacitor Hybrid Device.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• The demand for efficient and low-cost energy storage solutions is rapidly increasing.
• Hybrid devices combining battery and supercapacitor characteristics offer a promising approach to meet these demands.
• Potassium-based systems are attractive due to the abundance and low cost of potassium.

Purpose of the Study:

• To develop a novel, low-cost, nonaqueous potassium-based battery-supercapacitor hybrid device (BSH).
• To evaluate the electrochemical performance of this hybrid device for energy storage applications.
• To demonstrate the potential of this BSH for cost-effective electric energy storage systems.

Main Methods:

• Fabrication of a nonaqueous BSH using soft carbon as the anode and commercial activated carbon as the cathode.
• Utilization of potassium bis(fluoro-slufonyl)imide in dimethyl ether as the electrolyte.
• Comprehensive electrochemical testing to assess energy density, power density, and cycle life.

Main Results:

• The developed BSH achieved a high energy density of 120 W h kg^-1 and a high power density of 599 W kg^-1.
• The device exhibited an impressive long cycle life of 1500 cycles.
• Ultrafast charge and slow discharge performance was observed.

Conclusions:

• The successful establishment of this nonaqueous potassium-based BSH reconciles the advantages of potassium-ion batteries and supercapacitors.
• The achieved performance metrics highlight the potential of this hybrid device for advanced energy storage.
• This work demonstrates a significant step towards low-cost and efficient electric energy storage systems.