Nanoparticles-Dotted 3D Porous Nanofiber Skeleton Separator for Advanced Supercapacitors

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Supercapacitors (SCs) are crucial energy storage devices, with separators significantly impacting their energy density, power output, and safety.
• Current challenges in separator development include achieving a balance between large pore size, ultrathin dimensions, and robust mechanical properties.

Purpose of the Study:

• To develop an ultrathin composite separator with enhanced mechanical strength and large pore size for improved supercapacitor performance.
• To address the trade-off between mechanical integrity and porosity in ultrathin separators.

Main Methods:

• Fabrication of a 5 μm ultrathin separator using biaxial stretching, incorporating a 3D porous nanofiber skeleton and fumed aluminum oxide (Al2O3) nanoparticles.
• Optimization through an annealing process to enhance pore structure and nanoparticle integration.

Main Results:

• The developed separator exhibits a large average pore size of 130.8 nm and high mechanical strength of 40 MPa.
• Achieved low bulk resistance of 0.3 Ω and excellent thermal stability with zero shrinkage at 130 °C.
• Demonstrated superior performance compared to commercial separators due to enhanced electrolyte wettability and reduced ion transmission resistance.

Conclusions:

• The novel 3D porous nanofiber skeleton separator with fumed Al2O3 nanoparticles effectively resolves the conflict between mechanical strength and large pore size in ultrathin separators.
• The developed separator shows significant potential for advancing the large-scale application of next-generation energy storage devices.