Electrospun SiO2/PVDF copolymer composite nanofiber: Effect of SiO2 content on nanostructure, morphology, and thermal property

Abstract

A separator is an important part of lithium-ion batteries. Nanofiber separator is one promising material to improve the performance of lithium-ion batteries. SiO2/cPVDF composite nanofiber was successfully synthesis by the electrospinning process. SiO2 nanoparticle, cPVDF, and N-N DMAc were used to synthesis composite nanofiber. SiO2 content influences nanostructure, morphology, diameter and thermal property of nanofiber. Nanofiber separator prepared with the optimum condition of flow rate 0,004 mL/min, voltage 22 kV, and the distance to collector 13 cm. Structure of nanofiber separator was analyzed with ATR-FTIR. FTIR vibration band peak at 1057.8 cm-1 839.4 cm-1 and 761.3 cm-1 were related to Si-OH functional group, a distinctive β phase crystal and α phase crystal, respectively. The average diameter of cPVDF nanofiber, SiO2/cPVDF (0.5%) nanofiber, SiO2/cPVDF (0.75%), and SiO2/cPVDF (1%) were 648.3 nm, 320.6, 347.1, and 388.8 nm, respectively. Effect of addition of silica nanoparticles decreased the average diameter nanofiber. Electrospun SiO2/cPVDF composite nanofiber also showed different thermal behavior under different gases conditions in TGA study, and it is observed that the nanofiber separator could stand until near 400°C before the main chain's degradation occur. XRD and DSC analysis showed that increasing of SiO2 content decreased crystallinity of nanofiber composite. Water contact angle experimental results of SiO2/cPVDF composite nanofiber revealed an improvement of hydrophobicity with the addition of SiO2 on nanofiber composite.