[Polymer membrane] Sustainable Lithium-ion battery separators derived from Polyethylene oxide/Lignocellulose coated electrospun polyvinylidene fluoride-trifluoroethylene P(VDF-TrFE) nanofibrous membranes

Lithium-ion batteries gained extensive attention as an efficient energy storage systems like portable electronic devices such as laptops, mobile phones, calculators, digital cameras etc. *

Separator is one of the major components in lithiu -ion battery, which greatly influence the safety, ionic conductivity and electrochemical performance of the battery. Commercially available polyolefin-based separators suffer from low porosity, high thermal shrinkage, low electrolyte uptake, and retention, poor wettability with liquid electrolyte etc. This limits the use of lithium-ion batteries in electric vehicles and high-power applications.

Therefore, it is important to eliminate the above-mentioned drawbacks of separator. Many polymers and fabrication techniques are used to improve the electrochemical performance of the separator. Polyvinylidene fluoride-trifluoro ethylene is a copolymer of PVDF, well known for its excellent properties such as good mechanical strength, chemical inertness, thermal stability, piezo electric properties, non-toxic environment-friendly nature, etc.

The present study combines the advantages of P(VDF-TrFE) and sustainable lignocellulose. This ecofriendly separator material is prepared by combining the virtue of electrospinning and dip coating technique.This is a collaborative work, which is jointly carried out between Mahatma Gandhi University, Kottayam, Kerala, India and Institut Jean Lamour, University of Lorraine, Nancy France. In this work PEO/LIGC coated dimpled electrospun P(VDF-TrFE) nanofibrous separators were prepared by electrospinning technology and studied the the influence of PEO/LIGC coating on electrolyte uptake and electrochemical performance of electrospun P(VDF-TrFE) separator.

From this work, it is evident that the PEO/LIGC coating enhances the electrochemical performance of electrospun P(VDF-TrFE).  The electrolyte uptake of ecofriendly LIGC coated sample is ~ 440%, which is 647% higher than that of commercial Celgard separator. PEO/LIGC coated membrane shows ~ 86% porosity, which is 226% higher than that of the Celgard separator. Ionic conductivity studies show that dip coated P(VDF-TrFE) exhibits a conductivity 7.04 x 10-3 S cm-1.using the prepared  PEO/LIGC coated P(VDF-TrFE) separator, a 2320 type coin cell (Li/Separator/LiFePO4) were  fabricated and the electrochemical performance of the cell is superior to that of a Celgard 2320 separator.

A sustainable material such as lignocellulose has a remarkable potential to enhance the overall battery performance, which can be observed from the increased electrolyte uptake and ionic conductivity.

This study opens up new horizons for sustainable enhancement of lithium-ion batteries in the near future.

Title: Sustainable Lithium-ion battery separators derived from Polyethylene oxide/Lignocellulose coated electrospun P(VDF-TrFE) nanofibrous membranes

Authors: Bicy K, Deepa Elizabeth Mathew, Arul Manuel Stephen, Isabelle Royaud, Marc Poncot, Olivier Godard, Lionel Aranda, Didier Rouxel, Sabu Thomas

Journal: Surfaces and Interfaces, Elsevier

Date of publication (online): January 2022

Link: https://doi.org/10.1016/j.surfin.2021.101716

Image caption: Schematic representation of lithium-ion battery containing of PEO/LIGC coated electrospun P(VDF-TrFE) separator. The magnified image represents the PEO/LIGC coated electrospun P(VDF-TrFE) nanofiber