Mechanical and electrical properties of a polymer electrolyte based on zinc oxide for enhancement of Li-ion battery performance

Abstract

This work was carried out to synthesize and apply mesoporous 3-mercaptopropyl pyridine-ZnO nanorods (MPP-ZnO NRs) as additives in a cross-linked composite gel polymer electrolyte for enhancing the performance of lithium-ion batteries. The MPP-ZnO NRs were synthesized using a sol-gel method and functionalized with MPP. The electrospun fibrous polyacrylonitrile (PAN) membrane was coated with ZnO nanorods, forming a stable and robust composite electrolyte. Results of mechanical tests indicated that compared to control membranes (without ZnO NRs), the MPP-ZnO-containing membranes showed significant enhancements, likely an increase in tensile strength (∼1.5-fold), an enhancement in adhesion strength (∼4-fold), and an increase in shear stress (∼3-fold). Electrochemical performance was evaluated using charge-discharge cycling and AC impedance spectroscopy tests. Findings demonstrated that utilizing cross-linked gel-polymer electrolytes with MPP-ZnO NRs showed lower charge transfer resistance and superior cycling stability, maintaining 89.0 % capacity retention after 200 cycles at 0.5C, with an initial discharge capacity of 179.9 mAh/g and 160.1 mAh/g after 200 cycles. Moreover, these cells showed remarkable capacity recovery, with an18 % higher capacity at 5.0C compared to non-porous counterparts and delivering discharge capacity of 139.8 mAh/g at 5.0C. Results showed good high-rate performance due to improved thermal stability and HF scavenging ability of the mesoporous MPP-ZnO NR-based electrolyte. These results indicate the potential of mesoporous MPP-ZnO NRs in advancing the performance and stability of lithium-ion batteries, making them as low-cost candidates for future energy storage applications.