Design and Development of a High-Performance Gel Polymer Electrolyte for Na-Ion Battery from Halloysite Nanotube-Dispersed PVDF Nanofabrics

Electrospun poly(vinylidene fluoride) (PVDF)-based gel polymer electrolyte (GPE) is considered a highly promising candidate for a sodium-ion (Na-ion) battery because of its flexibility, light weight, 3D interconnected structure, and mechanical integrity. However, the pristine electrospun PVDF membrane-based GPE struggles to meet the prerequisite of Na-ion battery due to high crystallinity, low ionic conductivity, and deterioration of mechanical integrity. In order to overcome these issues, a nonwoven membrane was prepared comprising PVDF/halloysite nanoclay (HNT) nanocomposite (EPHN) as GPE for Na-ion batteries. The crystallinity and average fiber diameter for PVDF nanofibers decreased upon the addition of HNT. In contrast, the tensile strength, puncture strength, and dimensional stability of an electrospun PVDF membrane improved upon the addition of HNT. Due to high porosity (86%), electrolyte uptake (535%), and wettability, the ionic conductivity of the EPHN membrane (7.1 mS/cm) improved significantly compared with a pristine electrospun PVDF membrane along with augmented electrochemical stability (5.3 V). EPHN-based GPE exhibited a specific capacity of 162 mAh g–1 and a Coulombic efficiency of 98% after 100 cycles. EPHN-based GPE outperformed the pristine electrospun PVDF membrane and commercial polypropylene (PP) separator. The EPHN-based GPE in Na-ion batteries offers insight and approaches for further development of GPE to accomplish the properties demanded for real-world applications.