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## Studies on polymer electrolytes with new lithium borate salt

### Anna Lechnio

#### Abstract

The aim of this work was the synthesis and characterization of novel lithium borate salts for use in polymer electrolytes, which were obtained in the reaction of commercially available lithium compounds with Lewis acids. Then their spectral, thermal and electrochemical analysis was carried out. In the first part of the study, difluoro(alkoxy)borate derivative (ROBF2), previously obtained by thermal decomposition of CH3O(CH2CH2O)2BF3Li was used as a complexing agent. Commercial lithium salts LiX (X = PF6, ClO4, I, CF3SO3, N(CF3SO2)2), frequently appearing in the literature on polymer electrolytes were used as substrates for the reaction. Spectroscopic studies (NMR, FTIR) of the reaction products revealed that in all cases there was a clear interaction between the substrates. In further studies the synthesis and characterization of [2-(2-methoxyethoxy)ethoxy]ethyl lithium was carried out, in the complexation with boron trifluoride (BF3). Reaction conditions were selected to receive the maximum yield of the product. As a solvent for further synthesis THF was selected. Furthermore, it was found that the yield of the complex salt affects both the concentration of the solution and the mass used for the crystallisation of the salt. The largest yield obtained was about 80%. Spectral analysis showed that CH3(OCH2CH2)2OCH2C(O)OBF3Li is found in the crystal in the form of a stable dimer. This is due to interaction between the nucleophilic center of the chain and lithium cation. After adding a polar solvent the effect declines and the salt is found as a single molecule. Moreover, the results of mass spectroscopy indicated that as a result of providing enough energy to the complex undergoes degradation with production of BF3 and the carboxylic salt is formed. For further characterization of the product solid and gel electrolytes containing CH3(OCH2CH2)2OCH2C(O)OBF3Li and polymer matrix of poly(ethylene oxide) or a copolymer of vinylidene fluoride with hexafluoropropylene were obtained. Their thermal analysis by means of DSC technique was carried out, as well as their ionic conductivity was determined by means of impedance spectroscopy. The highest conductivity was obtained in electrolyte containing P(VDF-HFP) / EC / PC /salt. (10-5 S / cm at 20 ° C).
Record ID
Diploma type
Master of Science
Author
Anna Lechnio Anna Lechnio,, Undefined Affiliation
Title in Polish
badanie właściwości elektrolitów polimerowych z udziałem nowych boranowych soli litu
Supervisor
Ewa Zygadło-Monikowska (FC/CPCT) Ewa Zygadło-Monikowska,, Chair Of Polymer Chemistry And Technology (FC/CPCT)Faculty of Chemistry (FC)
Certifying unit
Faculty of Chemistry (FC)
Affiliation unit
Chair Of Polymer Chemistry And Technology (FC/CPCT)
Study subject / specialization
, Technologia Chemiczna
Language
(pl) Polish
Status
Finished
Defense Date
23-10-2012
Issue date (year)
2012
Keywords in Polish
-
Keywords in English
-
Abstract in Polish
urn:pw-repo:WUTc09dbd87d10a40fcadd3ce27ef1be607