量子化学DV-Xα研究
( 1. 重庆大学 化学化工学院， 重庆 400044;
2. 重庆师范大学 化学系， 重庆 400047)
摘 要: 采用原子基表示的第一原理赝势DV-Xα方法， 计算了锂离子电池正极材料LixMn2O4(x=0, 1, 2)各种模型的电子结构。 结果表明： 电极材料LixMn2O4具有较好的电子导电性， 锂离子嵌入正极材料后发生Jahn-Teller效应引起材料结构改变； 锂离子的净电荷变为+0.7（x=1）、 +0.9或+0.5（x=2）， 说明锂离子过度嵌入LixMn2O4中， 导致部分锂离子和氧离子的相互作用增强， 锂离子脱出较为困难， 从而容量降低。 最高占有轨道(HOMO)到最低空轨道(LUMO)的跃迁能很小， 电子较易进行嵌入和脱出。
关键字: 锂离子电池; LixMn2O4; 量子化学DV-Xα方法
electrode material LixMn2O4 for lithium ion battery
（ 1. College of Chemistry and Chemical Engineering,
Chongqing University,Chongqing 400044, China;
2. Department of Chemistry, Chongqing Normal University, Chongqing 400047, China）
Abstract: By employing the “atomic-basis+norm-conserving non-local pseudopotential” first principle quantum chemical DV-Xα method, the electronic structure of electrode materials LixMn2O4 (x=0, 1, 2) for lithium ion battery was studied. The calculating results show that all these three materials have good electronic conductivity, and the Jahn-Teller distortion and the change of structure in the electrode material after intercalation of lithium ion. The net charge of lithium ion is +0.7, +0.9 and +0.5 when x is 1 and 2, respectively. This indicates that the interactions between lithium ion and oxygen ion are increased for the excessive intercalation of lithium ion, so the deintercalation of lithium ion becomes more difficult and the reversible capacity of the electrode is decreased. While the electron intercalates and deintercalates easily due to the smaller energy that orbit leaps from the HOMO orbit to the LUMO orbit.
Key words: lithium ion battery; LixMn2O4; quantum chemical DV-Xα method
