Crosslinked perfluoropolyether solid electrolytes for lithium ion transport

Abstract

A B S T R A C TPerfluoropolyethers (PFPE) are commercially available non-flammable short chain polymeric liquids. Endfunctionalized PFPE chains solvate lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt and these mixtures can be used as electrolytes for lithium (Li) batteries. Here we synthesize and characterize a new class of solid PFPE electrolytes. The electrolytes are made by either thermal or UV crosslinking PFPE chains with urethane methacrylate end-groups. For the synthesis of thermally crosslinked electrolytes, polyhedral oligomeric silsesquioxane (POSS) with organic acrylopropyl groups was used as crosslinker agent, while for UV cured electrolytes a photoinitiatior was used. We present thermal, morphological, and electrical data of the solid electrolytes. We compare these properties with those of the two parent liquids (PFPE with urethane methacrylate end-groups and POSS with acrylopropyl groups) mixed with LiTFSI. The solubility limit of LiTFSI in the PFPE-based solids is higher than that in the liquids. The conductivity data are analyzed using the Vogel-Tamman-Fulcher equation. The concentration of effective charge carriers is a strong function of the nature of the solvent (solid versus liquid) whereas the activation energy is neither a strong function of the nature of the solvent nor salt concentration.

Hybrid Solid Polymer Electrolytes with Two‐Dimensional Inorganic Nanofillers

“…VTF is closely relatedt ot he free volume model where there is ad istribution of voids through the polymer matrix broughta bout by polymer motion. The electrochemical window largely depends on the conductive salt used for the nanocomposite and density functional theory calculations performed by Pandiana nd colleagues [60] with PEO/Li-salt composites determined that the cathodica nd anodic limits were determined by the anion and monomer repeat units, respectively.S ubstitution of ethylene chainsw ith fluorine atoms resulted to an extended potential window and correlating to the satisfactory experimental results of Devauxa nd group, [61] development of perfluorinated SPEs may be the next step in the field of solid-statee lectrolytes. Use of this model to fit experimental data is only valid when there is only as ingle existingp hase and provided that the polymer is amorphous.…”

“…The electrochemical window largely depends on the conductive salt used for the nanocomposite and density functional theory calculations performed by Pandian and colleagues with PEO/Li‐salt composites determined that the cathodic and anodic limits were determined by the anion and monomer repeat units, respectively. Substitution of ethylene chains with fluorine atoms resulted to an extended potential window and correlating to the satisfactory experimental results of Devaux and group, development of perfluorinated SPEs may be the next step in the field of solid‐state electrolytes.…”

Structure, morphology, thermal and conductivity properties of gel electrolyte system based on polyvinyl chloride and LiClO4

“…Using the data of the impedance test in the Li-MnO 2 system it was shown that the conductivity of the PVC-PC-LiClO 4 gel electrolyte is 5  10 -4 S/cm at room temperatures. This value is in excess of the conductivity for liquid (~3  10 -4 S/cm) [10,11] and solid (~10 -5 S/cm) [12,13] electrolytes. Singleparticle and collective dynamics of solvent molecules (PC and PC-LiClO 4 ) in free state and in the pores of polymer gels based on PVC in the ranges of observation times 10 -10 -10 -12 s were determined by quasi-elastic neutron scattering technique.…”

Building Better Batteries in the Solid State: A Review

“…This prompts further research on solid PFPE-based electrolytes, as they are not limited in the anodic domain. Fluorinated solid PFPE/LiTFSI was synthesized with urethane methacrylate end-groups [278] but have not yet been tested as electrolytes. Finally, we note that the polymers and copolymers that compose the electrolytes that we have mentioned are linear.…”