Electrochemical and Spectroscopic Properties of Electrospun PAN-Based Fibrous Polymer Electrolytes

Abstract

Microporous fibrous polymer electrolytes were prepared by immersing electrospun poly͑acrylonitrile͒ ͑PAN͒-based fibrous membranes into lithium salt-based electrolytes. They showed high ionic conductivities of up to 1.0 ϫ 10 −3 S/cm at 20°C, and sufficient electrochemical stabilities of up to 4.5 V. Their ion conduction depended on the physicochemical properties of the lithium salt-based electrolytes trapped in pores, as well as on the interactions among the Li + ion, the carbonate, and the PAN. From the Fourier transform-Raman data, lithium ion transport was mainly achieved by the lithium salt-based electrolytes in pores via the interaction between the Li + ion and the C=O group of carbonate molecules, and was also affected by the PAN through the interaction between the Li + ion and the CϵN groups of PAN. Their electrochemical stabilities were enhanced by the swelling of the electrospun PAN nanofibers because of the dipolar interaction between the CϵN groups of PAN and the C=O groups of carbonate in the lithium salt-based electrolytes. Prototype cells using electrospun PAN-based fibrous polymer electrolytes thus showed different cyclic performances, according to the composition of the lithium salt-based electrolytes. The prototype cell with 1 M LiPF 6-ethylene carbonate/dimethyl carbonate ͑1/1͒ showed the highest discharge capacity and the most stable cyclic performance among them.

Polymethylmethacrylate/Polyacrylonitrile Membranes via Centrifugal Spinning as Separator in Li-Ion Batteries

“…In addition, the variations in physical contact caused by the different separator morphology may also play a role in changing the electrochemical oxidation limit. These explanations are in agreement with earlier studies, which reported that electrolyte-soaked PAN fibrous membranes had improved electrochemical stability due to the high affinity of these membranes to the liquid electrolyte [27,28]. …”

“…Jung et al [26] reported increased electrochemical oxidation limit for PAN fibrous separators due to the good electrolyte absorption resulted from high specific surface area and thin fiber diameter. Raghavan et al [27] and Choi et al [28] also reported that the electrolyte-soaked fiber membranes with large surface area had improved electrochemical oxidation limit due to the formation of a large amount of complex compounds such as associated Li + -N≡C-group, associated Li + -O=C group, and associated C≡N-Li + -O=C group. Large and fully interconnected pores, high porosity, high specific surface area, uniform morphology were also reported as reasons of increased electrochemical oxidation limits when the average fiber diameter of fibrous separators decreased [27].…”

Preparation of PVdF-based electrospun membranes and their application as separators

“…Recently, microporous polymer electrolytes composed of electrospun membranes made of PVdF, P(VdF-HFP) and PAN have been developed by Lee and co-workers [1][2][3][4]. These electrospun membranes are composed of ultrafine fibers with diameters in the range of tens of nanometers to several micrometers.…”

Electrospun polyacrylonitrile-based carbon nanofibers and their hydrogen storages

“…There is a growing interest in the electrospinning process of polymer solution or melt because of their several potent applications such as sensors, polymer electrolytes for lithium ion polymer battery, dye-sentized solar cell etc.. [10][11][12][13][14] Electrospinning is a powerful method of producing polymeric ultrafine fibers within the range of a few nanometers to a few hundred nanometers in diameter, which cannot be easily obtained using the traditional methods for making fibers. 15 Nano-sized fibers may be more helpful in obtaining carbon materials with well-defined pore structure compared to the carbonization of micro-sized polymer fibers.…”