Dual-Modified Electrospun Fiber Membrane as Separator with Excellent Safety Performance and High Operating...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Developing advanced separators is crucial for enhancing lithium-ion battery safety and performance.
• Existing separators often face limitations in thermal stability, mechanical strength, and electrolyte wettability.

Purpose of the Study:

• To fabricate a novel electrospun fiber membrane (PB3N1BN) with enhanced properties for lithium-ion battery applications.
• To investigate the structural and electrochemical performance of the PB3N1BN membrane.

Main Methods:

• Fabrication of PB3N1BN membrane via electrospinning of a homogeneous suspension containing Polyacrylonitrile (PAN), Boric acid (H3BO3), Melamine (C3H6N6), and delaminated Boron Nitride nanosheets (BNNSs).
• Preparation of BNNSs through delamination of bulk hexagonal Boron Nitride (h-BN) assisted by Polyvinylpyrrolidone (PVP).
• Characterization of membrane properties including mechanical strength, thermal stability, electrolyte wettability, and flame retardancy.

Main Results:

• The PB3N1BN membrane demonstrated excellent mechanical properties (19.1 MPa), high thermal dimensional stability (no contraction at 200 °C), and superior flame retardancy (minimum heat release of 3.2 MJ m⁻²).
• The membrane exhibited good electrolyte wettability with a contact angle of approximately 0°.
• Assembled LiFePO4/PB3N1BN/Li batteries showed high capacity (169 mAh g⁻¹ at 0.5 C), exceptional rate capability (129 mAh g⁻¹ at 5 C), and prominent cycling stability over 400 cycles.
• The battery maintained a discharge capacity of 152 mAh g⁻¹ at 80 °C.

Conclusions:

• The developed PB3N1BN electrospun fiber membrane offers a promising solution for high-performance lithium-ion batteries.
• The incorporation of BNNSs significantly improves the separator's mechanical, thermal, and flame-retardant properties.
• This work presents a new design strategy for advanced battery separators with enhanced safety and durability.