Description
The using up of natural resources promotes the development of studies concerning seeking of new methods of acquiring energy, as well as development of known solutions, mainly chemical sources of energy. Lithium-ion batteries find increasing commercial importance being applied in many fields of technics. It is expected that they will fulfill an important role as systems for storage of energy achieved from renewable sources. However, many aspects connected with the production of lithium batteries for these applications is still problematic which limits the use of them. The objective of the project are new membranes for use in lithium-ion batteries as separates capable of ionic conduction of electric current. It is expected that the studies carried out will result in obtaining electrolytes permitting obtaining of improved parameters in lithium-ion batteries. An increase in electrochemical parameters will be achieved by using new complex salts obtained in the reactions with boron and aluminum derivatives. It is expected that manufacturers of components for lithium-ion derivatives will benefit from the present studies.
Summary of project results
The main goal of this project was the obtaining of a new group of polymer electrolytes for application in lithium-ion batteries, characterized by high participation of lithium cations in electric charge transport. Anions are the dominating electric charge carriers in electrolytes hitherto used, which leads to concentration polarization and causes worsening of the cell operation characteristics. Gaining a considerable increase in the lithium cations transference numbers in polymer electrolytes may assure rechargeable chemical cells a longer time of operation, smaller drop in capacity in charging-discharging cycles and possibility of obtaining larger current densities. Obtaining of this type of electrolytes is one of the basic conditions for development of lithium-ion battery technology for application in portable electronic devices as well as in large batteries for charging vehicle engines and storage of energy acquired from renewable sources. Within this project, modification of electrolytes was carried out by complexation of lithium ion salts with derivatives of Lewis acid properties. Boron and aluminum compounds elaborated within the project were utilized in the complexation reaction. Electrochemical studies of polymer electrolytes using these derivatives indicate an increasing immobilization of salt anions. The best results were obtained for difluoroalkoxy-carboxyborates, for which the participation of cations in electric charge transport was 80-87%. New complex salts of ionic liquid properties were obtained from the reaction of lithium salts with that derivative. The second achievement of the project were new aluminum carboxylate derivatives, which strongly interact with lithium salts forming complex linkages, the structure of which depends on the salt anion and reaction conditions. Polymer electrolytes involving aluminum carboxylates show very good mechanical properties. Studies carried out allowed the principal investigator to complete her habilitation work.
Summary of bilateral results