Preparation And Electrochemical Properties Of Titanate Anode Materials For Lithium Ion Batteries

Li₄Ti₅O₁₂ with spinel structure has the advantages of stable structure,good cycle performance and easy preparation,but it also has disadvantages such as low ion conductivity.In view of the shortcomings of the negative electrode material Li₄Ti₅O₁₂,ion doping is one of the most effective modification methods.In the aspect of the synthesis of Li₄Ti₅O₁₂ anode materials:Li₄Ti₅O₁₂ anode materials at different temperatures and different times were synthesized using mechanochemical methods with lithium metatitanate as raw materials.The morphology of the materials was characterized by XRD and TEM,and the materials were subjected to AC impedance through electrochemical workstations.And cyclic voltammetry,the electrochemical test was carried out on the material with the blue electric test system,which showed that the anode material Li₄Ti₅O₁₂ synthesized under the calcination condition of 800℃-12h has the best electrochemical performance.The material was synthesized by high-temperature solid-phase method at 800℃-12h as a comparison.It was found that the material had large particle size,serious agglomeration,low first-week discharge specific capacity,and poor cycle stability.Modification:sodium ions are selected for doping to lithium sites,and Li_4-xNa_xTi₅O₁₂ anode materials with different doping amounts are synthesized by high temperature solid phase method.The doped materials have significantly higher first week discharge specific capacity.When x=0.05,the first week discharge specific capacity of the material is the highest.The mixed Li_4-xNa_xTi₅O₁₂ negative electrode materials with different ratios of lithium to sodium were designed and synthesized.As the value of x increases,the specific discharge capacity in the first week decreases and the charge transfer resistance increases.In the synthesis of Na₂Ti₃O₇ anode material:mechanochemical method was used to explore the influence of temperature and calcination time on the electrochemistry of the material,and it was shown that the best synthesis condition was calcination at 850℃for 12h.In terms of the synthesis of Li Na Ti₃O₇ anode materials:mechanochemical methods were used to explore the influence of temperature and calcination time on the electrochemistry of the materials,and it was shown that the best synthesis conditions of the materials were 800℃,14h.Compared with Na₂Ti₃O₇ anode materials,Li Na Ti₃O₇ anodes had better Small particle size,lower voltage platform and more stable electrochemical performance and minimum impedance.