PVDF-HFP-modified gel polymer electrolyte for the stable cycling lithium metal batteries

Abstract

• Preparation of a novel type of inorganic fast ion conductor and organic polymer composite electrolyte. • High ionic conductivity of 9.4 × 10 −4 S cm −1 at 30 ℃ and lithium-ion transference number of 0.66. • Excellent rate performance and cycling stability. Gel polymer electrolytes (GPEs) is a promising electrolyte due to its processability and flexibility. However, the low ionic conductivity of GPEs remains huge challenges to hinder their development. Herein, a novel composite gel polymer electrolytes membrane consisting of Li 1.7 Al 0.3 Ti 1.7 (PO 3 ) 4 (LATP) ceramic powders, poly (propylene carbonate) (PPC) and poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) is designed and constructed via a solution-casting method. The morphology, structure and electrochemical properties of the gel polymer electrolyte modified by LATP are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and electrochemical technology. It has been found that the as-prepared composite GPEs exhibit the higher ionic conductivity of 9.4 × 10 −4 S cm −1 at 30 ℃, a wider electrochemical window of 5.2 V and a higher lithium-ion transference number of 0.66 than currently reported other analogous electrolytes. In the same time, it also shows good mechanical properties. As a result, LiFePO 4 |Li battery with PVDF-HFP-based membrane delivers excellent cycling stability. Therefore, the study indicates that PVDF-HFP-based composite GPEs possesses the potential application prospect in high performance lithium metal batteries (LMBs).