Composite Polymer Electrolyte Based on PAN/TPU for Lithium-Ion Batteries Operating at Room Temperature

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Lithium-ion batteries are crucial for next-generation technologies due to high energy density and lifespan.
• Traditional organic liquid electrolytes pose safety risks (explosive, volatile, toxic).
• Composite polymer electrolytes (CPEs) offer enhanced safety and stability but often require material optimization.

Purpose of the Study:

• To develop and characterize a novel composite polymer electrolyte (CPE) for improved lithium-ion battery safety and performance.
• To investigate the electrochemical properties and stability of the optimized CPE.
• To evaluate the performance of a lithium-ion battery utilizing the developed CPE.

Main Methods:

• Solution casting technique used to prepare the CPE from polyurethane (TPU), polyacrylonitrile (PAN), Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) ceramic filler, and LiClO₄.
• Optimization of formulation with 40 wt% TPU, 60 wt% PAN, and 10 wt% LATP.
• Electrochemical characterization including ionic conductivity, lithium-ion transference number, and electrochemical stability window.
• Assembly and testing of a LiFePO₄/Li battery using the CPE.

Main Results:

• Optimal CPE formulation (40 wt% TPU, 60 wt% PAN, 10 wt% LATP) achieved ionic conductivity of 2.1 × 10^-4 S cm^-1 and a lithium-ion transference number (t_Li⁺) of 0.60 at 30 °C.
• Demonstrated notable electrochemical stability and robust safety performance.
• LiFePO₄/Li battery exhibited excellent cycling stability and rate capability at room temperature.
• Delivered 130 mAh g^-1 at 1C and 168 mAh g^-1 at 0.2C, retaining 98% capacity after 100 cycles at 25 °C.

Conclusions:

• The developed composite polymer electrolyte offers a promising, safer alternative to conventional liquid electrolytes for lithium-ion batteries.
• The optimized blend of TPU, PAN, and LATP enhances ionic conductivity and electrochemical stability.
• The CPE demonstrates excellent potential for practical application in high-performance and safe lithium-ion batteries.