Surface Work Function-Induced High-Entropy Solid Electrolyte Interphase Formation for Highly Stable Potassium Metal...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid electrolyte interphase (SEI) layer failure is a critical challenge for potassium metal battery practical application.
• Developing stable SEI layers is essential for advancing high-performance energy storage devices.

Purpose of the Study:

• To design and construct a novel high-entropy SEI layer for potassium metal anodes.
• To investigate the formation mechanism and properties of the in situ generated SEI layer.
• To evaluate the electrochemical performance of potassium metal batteries utilizing the engineered SEI.

Main Methods:

• In situ electrochemical conversion of Sn3O4/Sn2S3 interfacial layer on a porous scaffold.
• Theoretical studies and experimental techniques to analyze the heterostructure and SEI properties.
• Electrochemical testing of symmetric cells and full cells with a perylene-3,4,9,10-tetracarboxylic dianhydride cathode.

Main Results:

• A high-entropy SEI layer with low surface roughness, low surface potential, and fast ion transport was successfully formed.
• The engineered SEI layer demonstrated excellent mechanical properties (Young's modulus of 20.08 GPa).
• Potassium metal anodes exhibited superior rate performance (up to 10 mA cm-2) and cycling stability (2500 h at 0.5 mA cm-2).
• Full batteries retained 81.6% capacity over 1650 cycles at 10 C.

Conclusions:

• The developed high-entropy SEI layer effectively suppresses SEI failure in potassium metal batteries.
• This approach provides a straightforward and efficient strategy for creating stable interphases on metallic potassium anodes.
• The findings pave the way for practical applications of high-performance potassium metal batteries.