Research On Preparation Of Lithium Battery Electrode Material Li₄Ti₅O₁₂Using Molten Salt Method

In this paper, the influencing factors of preparing lithium titanate(Li4Ti5O12) using molten salt method were systematically studied. And the mechanism of preparing Li4Ti5O12using molten salt method was preliminary discussedand, the electrochemical performances of Li4Ti5O12as negative materials of lithium batteries including the cycle and rate performances were tested and characterized. The main results are as follows:(1) The working reaction media is selected as LiCl-KCl system due to its low viscosity and inert property to the active materials of LiOH·H2O and TiO2, and the molten salts used to prepare Li4Ti5O12is composed of LiCl-KCl-LiOH·H2O-TiO2.(2) Under the condition of the same holding time, when the calcination temperature researched800℃, the crystal shape of the products was more complete, the dispersion was smaller, and the specific surface area was larger; At this temperature, when holding time reached4h, the particle size is samaller, about3μm, the dispersion was smaller, and the specific surface area was larger; Under the condition of800℃-4h, when the molten salt ratio N=2, the particle size was smaller, about2.5μm. And the smaller the particle size of the reactant was, the smaller the particle size of the product would be.(3) Under the condition of800℃-4h, stirring could reduce the particle size of the product effectively, the particle size was about2μm forming by many little particles about200nm, the particles were most uniform, the specific surface area was largest.Therefore the product particles become uniform, the surface become rough, and the specific surface area was increased. When the products were used as the negative materials of lithium battery,, the cycle and rate performances were better:The first discharge capacity was152mAhg-1, the capacity conservation rate was78%at0.2C after50cycles, the coulombic effiency was more than99%.At0.2C、0.5C、1C、2C、5C different discharge rate,25cycles later, the discharge capacity was40mAhg-1; The smaller the particle size of Li4Ti5O12was, the uniform the product was,the large the specific surface area was,the electrochemical property would be.(4) Blowing air into the reactants could reduce the product particle size, but the uneven air increased the product dispersion.(5) Under the experimental conditions, preparing Li4Ti5O12using molten salt method complied with template mechanism.