The Synthesis And Performance Of Lithium Boron Salt Electrolyte For Lithium Ion Battery:dicyanomethylene Croconic Acid Derivatives

With the rapid development of the economy, the energy is the core of the development. The society pays attention to the development and application of secondary energy. Chemical energy is one of energies, and becomes necessity of social development. So storage battery is the key of chemical energy field, which is characterized by long cycling life, improved chemical-performance and green environmental protection. The development of storage battery goes through a period from lead acid storage battery to lithium ion battery with rocking-chair character. The stage of development of storage battery is the base of improving electrochemical performance. Lithium-ion battery is a new kind of green electrochemical energy. It not only thoroughly solved safety issues of old battery, but also increased cycling life. So far, lithium-ion battery has been applied widely, such as electro vehicle and portable electronic equipment. Therefore, the study on lithium-ion battery is one of the hottest topics.Electrolyte is one major part of Lithium-ion battery, its performance directly affects the performance of Lithium-ion battery. Searching for new-style electrolyte is very important, dicyanomethylene croconic acid, pyrocatechol, Perfluorobenzene-1,2-diol, fluorine ion can coordinate with B to form a big integration anion. and to form many lithium salts combining with the lithium ion, which have new structures and good electrochemical performance.This thesis mainly introduces synthesis and characterization of three kinds of new electrolytes, and their electrochemical performance.This thesis includes four chapters as following:Chapter1, introducing profile and developments in the field of lithium ion battery. Summarizes the advances synthetic methods for designing new lithium salts.Chapter2, introducing the synthetic methods of new lithium salts. Three kinds of new lithium salt are Lithium[dicyanomethylene croconate,1,2-benzenediolate(2)-o,o’]borate, lithium[dicyanomethylene-croconate,3,4,5,6-fluoro-1,2-benzenediolate(2)-o,o’]borate and lithium[dicyanomethylene-croconate,difluoro]borate, which have been characterized by ICP and NMR analysis.Chapter3, the electrochemical performance of new lithium salts including thermal stability, the conductivity, the oxidation potential and the solubility has been investigated. Their thermodynamic properties and electrochemical performance have been studied also.In summary, this thesis reports the synthesis of three new lithium salts, and analysis of their structures and electrochemical performance. The results show that the lithium salts have good features including good solubility, high conductivity and oxidation potential. They have the potential of becoming commercialization Lithium-ion battery electrolyte which are the base of the research and development of lithium salts in the future.