Direct Fluorination Strategy to Enhance Energy Storage Performance of Biaxially-Oriented Polypropylene Films for...

Area of Science:

• Materials Science
• Polymer Science
• Energy Storage

Background:

• Polymer dielectric films are crucial for energy storage applications.
• Traditional biaxially oriented polypropylene (BOPP) films exhibit limitations at elevated temperatures.
• Advanced capacitors require materials with improved thermal stability and energy density.

Purpose of the Study:

• To develop a novel fluorinated BOPP (FBOPP) film for high-temperature energy storage applications.
• To enhance the dielectric properties and energy density of BOPP films.
• To provide a scalable manufacturing method for high-performance dielectric films.

Main Methods:

• A two-step process involving direct fluorination followed by biaxial stretching of polypropylene (PP) sheets.
• Surface modification to create an island-like structure on FBOPP films.
• Characterization of the FBOPP films' electronic properties and performance in capacitors.

Main Results:

• FBOPP films exhibit enhanced electron affinity due to fluorine incorporation, lowering the LUMO level.
• The surface fluorinated layer acts as electron traps, inhibiting electron injection and transport.
• FBOPP films achieved a maximum discharge energy density of 1.34 J cm⁻³ at 120°C with 90% charge-discharged efficiency, a 197.8% improvement over BOPP.
• The proposed strategy is compatible with existing industrial processes for large-scale production.

Conclusions:

• The facile two-step strategy effectively produces FBOPP films with enhanced dielectric properties for high-temperature applications.
• FBOPP films represent a promising material for next-generation high-performance capacitors.
• The developed method offers a scalable and industrially viable approach for manufacturing advanced dielectric films.