Experimental Research On Synthesis And Properties Of Electrolyte With Derivatives Of Croconic Acid For Li-ion Batteries

Since the early 1990s, the lithium-ion batteries have successfully entered the market, then, it is begun to be commercial production. Lithium-ion battery output voltage is usually three times than nickel-cadmium batteries or nickel metal hydride battery, the output power is the same amount twice the size of a nickel-cadmium batteries. Therefore, the lithium-ion batteries in the future will inevitably become an important force in the field of new energy. Lithium salt electrolyte is the main component of lithium-ion batteries, impacting on battery performance. Therefore, developing a higher ionic conductivity, better solubility, good chemical, electrochemical and thermal stability, and reflecting the green of safe and nontoxic lithium-ion battery electrolytes are the main research directions in the future. According to the requirements of development of lithium-ion battery electrolytes, we have designed and synthesized of the electrolyte by lithium with derivatives of croconic acid for lithium-ion batteries. In this type of electrolyte, the lithium-ion combines with a large chelating anion, which a B is in the centre. It has electron withdrawing substituents. In addition, in the anion coordination with the B is oxygen. The anion is distributed the center negative charge ions with a largeπconjugation. So the major anion is more stable. The lithium borate salts have good electrochemical properties.This paper is divided into four chapters.In the first chapter, summarizing of the characteristics of lithium ion batteries, overview of its components, electrolyte status and development prospects, these will help the formation of the paper.In the second chapter, a series of lihium borates are synthesized including Lithium[1,2-(cyanoamino)-3-oxo-4-cyclopentene-4,5-diol croconato]borate, Lithium bis[1,2-(cyanoamino)-3-oxo-4-cyclopentene-4,5-diol]borate. They were characteri zed by IR, elemental analysis, ICP. In the third chapter, electrochemical properties of lithium borates salts with derivative of croconic acid were studied. We mainly analysis the properties of the lithium salts in solubility, electrical conductivity, thermal stability, oxidation potential aspects. The electrochemical and thermodynamic aspects of the features were also studied.In the fourth chapter, about thesis conclusions and future prospects, innovative lithium-ion battery electrolytes and future trends were discussed mainly from the development of lithium-ion battery electrolytes and general requirements.Generally, two organic lithium salts are synthesized. They have good solubility, high electrical conductivity, oxidation potential. Battery-level requirements of the new lithium-ion battery electrolytes are obtained.