Modification And Electrochemical Performance Of Li₄Ti₅O₁₂ Anode For Lithium-ion Battery

The spinel structure Li4Ti5O12material is a promising negative electrode materials for lithium-ion batteries, because this material exhibits some unique and useful characteristics. Li4Ti5O12exhibits excellent cycling performance due to its no structural change called as zero-strain insertion. It has many advantages in reversibility, safety performance, and environmental protection and so on. Unfortunately, its low electronic conductivity has limited its applications of fast charging and discharging at high power rates.In order to enhance the electrochemical performance, the surface modifications of Li4Ti5O12materials prepared by solid-state reaction method have been investigated. The structure and morphology characteristics of the composites were investigated by XRD, SEM. The electrochemical properties were tested through CV, EIS and charge-discharge test.Firstly, the electrode slices of Li4Ti5O12were prepared. Then, using the magnetron sputtering, their surfaces were evaporated by an Al-doped ZnO (AZO) films. The surface modification The experimental results indicate that AZO surface medication gives rise to the enhancement of electric conductivity for Li4Ti5O12electrodes. As a result, The better rate performance and cycling performance are achieved.Secondly, Li4Ti5O12/ZnO composites have been synthesized by a mechanical milling method,In comparison with the pristine Li4Ti5O12, Li4Ti5O12/ZnO is demonstrated to have superior electrochemical performance in wide operation temperatures, especially at high discharging rates. The analysis of the electrical properties and electrochemical measurements reveal that Li4Ti5O12/ZnO has much lower charge-transfer resistances, especially at low temperature.Lastly, in same method, the Li4Ti5O12/Ge composites were successfully prepared through the solid-state reaction technique. Moreover, the effects of Ge-coating on electrochemical performances of Li4Ti5O12was studied. The experimental results indicate that Ge surface medication gives rise to the enhancement of electric conductivity and the improvement of rate performance and cycling performance.