Thermodynamics And Electrochemisty Research Of The Electrolytes Solution On The New Lithium Salt

Since the highest gravimetric and volumetric energy densities, lithium-ion batteries have become one of the most important commercially produced rechargeable batteries. Combined with developments of electric vehicles and hybrid electric vehicles, people need a better performance of lithium-ion batteries to meet future energy needs. The development of 5 V cathode materials and an electrolyte with wide electrochemical window that can provide stable cycling performance at high voltage is of great importance for power battery applications. The interaction of lithium-ion solvent in lithium-ion power battery electrolyte is key factor and affects the battery performance. At present, more and more traditional electrolyte of lithium-ion battery can not meet the people is expectations and requirements for power battery in high power, safety and low temperature. Based on the requirement of above this thesis mainly studies the new lithium( LiBOB) thermodynamic properties and electrochemical properties of the electrolyte solution.1、 The solubility data of Lithium bis(oxalate)borate were measured in six different solvents using the synthetic method and laser monitoring technique at temperatures ranging from 293.15 K- 363.15 K. The experimental solubilities of LiBOB in different solvents were correlated by the modified Apelblat equations. It is found the calculated solubility data show good consistency with the experimental values. Based on it, some thermodynamic parameters of LiBOB in different solvents, such as dissolution enthalpy, dissolution entropy and dissolution Gibbs free energy, are also calculated. These results concerning the solubility of LiBOB in above solvents will provide fundamental data in the commercial application of Li BOB.2、Precise measurements of viscosity, density and conductivity of lithium bis(oxalate)borate(Li BOB) in dimethyl sulfoxide(DMSO), N,N-dimethylfomamide(DMF) and ?-butyrolactone(GBL) are reported at(293.15- 333.15) K. The conductivity, density and viscosity measurements of the aqueous systems were found to decrease as the temperature increase at fixed concentration and the values increase as the salt concentration increase at fixed temperature. Based on it, the conductometric apparent activation energy(Ea) and thermal expansion coefficients(α) are calculated, the viscosity data have been analyzed by the Jones-Dole equation. The activation parameters have been evaluated using transition-state treatments of Eying and Feakins. These results concerning the conductivity, density and viscosity of LiBOB in above solvents will provide fundamental data in the commercial application of LiBOB.