Gel Polymer Electrolytes Based on Silica-Added Poly(ethylene oxide) Electrospun Membranes for Lithium Batteries.

Maria Navarra,Lucia Lombardo,Pantaleone Bruni,Leonardo Morelli,Stefania Panero,Akiko Tsurumaki,Fausto Croce

doi:10.3390/membranes8040126

Maria Navarra, Lucia Lombardo + Show 5 more

Open Access

https://doi.org/10.3390/membranes8040126

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Abstract

Solid polymer electrolytes, in the form of membranes, offering high chemical and mechanical stability, while maintaining good ionic conductivity, are envisaged as a possible solution to improve performances and safety in different lithium cell configurations. In this work, we designed and prepared systems formed using innovative nanocomposite polymer membranes, based on high molecular weight poly(ethylene oxide) (PEO) and silica nanopowders, produced by the electrospinning technique. These membranes were subsequently gelled with solutions based on aprotic ionic liquid, carbonate solvents, and lithium salt. The addition of polysulfide species to the electrolyte solution was also considered, in view of potential applications in lithium-sulfur cells. The morphology of the electrospun pristine membranes was evaluated using scanning electron microscopy. Stability and thermal properties of pristine and gelled systems were investigated uisng differential scanning calorimetry and thermal gravimetric analysis. Electrochemical impedance spectroscopy was used to determine the conductivity of both swelling solutions and gelled membranes, allowing insight into the ion transport mechanism within the proposed composite electrolytes.

Highlights

Intense research efforts are still directed to improve the characteristics of lithium battery devices for energy storage
When nanoparticles were added to poly(ethylene oxide) (PEO) solution, the resulting fibers showed slightly higher diameter that can be explained by the inclusion of silica particles inside the polymer fibers
An easy way to obtain highly conductive gel polymer electrolytes was proposed in this paper

Summary

Introduction

Intense research efforts are still directed to improve the characteristics of lithium battery devices for energy storage. The second strategy involves the use of lithium salts with low lattice energy, which favors the lithium salt dissociation To achieve this goal, lithium salts with large and flexible anions, that disperse effectively the charge and are able to increase the free-volume between the polymer chains and to promote the ionic mobility, have been used [8,12,13]. Emphasis is given to the analysis of the conducting properties of the proposed systems as a figure of merit in view of applications in electrochemical devices Such electrolytes consist of nanocomposite polymer membranes of PEO/silica produced through the electrospinning technique and gelled using two liquid solutions. The TFSI anion is the same contained in the ionic liquid, which should avoid the Li+ -ion transference number reduction, possibly occurring when additional ionic species are added to the solution [21]

Membrane Separators Fabrication

Swelling Solutions

Characterizations

Results and Discussion

Conclusions