First-Principles Studies Of Li₄Ti₅O₁₂ Anode Material For Lithium Ion Batteries

The first-principles PAW pseudopotential method within the generalized gradient approximation(GGA) based on the density functional theory(DFT) is employed to investigate mainly the following three questions.1:The geometry and electronic structure of the bulk cathode material Li4Ti5O12 have been studied by first principles calculations. The total density of states, partial density of states, band structure and valence electron charge density contours has been shown. On one hand, we want to obtain the theory lattice constant and electronic structure; on the other hand, the PAW+GGA method will be justifed by comparing with results attained by other theoretical or experimental methods. It is found that the results obtained by our calculations are in good agreement with other theoretical results and experimental datas.2:The local and electronic structures of Li4+xTi5O12 have been studies in details. The total density of states and partial density of states have also been studied in details. The results suggest that Li4Ti5O12 can be lithiated to the state of Li8.5Ti5O12. The theoretical capacity is approximately 1.5 times as the capacity of an anode working between Li4Ti5O12 and Li7Ti5O12.3:The first-principle calculations based on the denstiy functional theory also employed to investigate the Li4Ti5O12 (100), (110) and (111) surfaces. And the electronic structures of surfaces have been studied in details. The result show that (100) is the most stable surface and the electronic structures of interlayer Ti atoms are similar as the bulk's but the outlayer Ti atoms are not.