纳米Li_4Ti_5O_(12)中锂离子扩散系数的测定和解析

Determination and analysis of lithium diffusion coefficient in Li_4Ti_5O_(12) cathode material

以纳米Li4Ti50诬正极材料为研究对象，采用恒电位间歇滴定法（PITT）测定固相材料LiTiO5O12中u＋的扩散速率，解析u＋在纳米Li4Ti5O12充放电过程中的扩散行为。结果表明：测得的锂离子在活性材料中的扩散系数为10-12～10-12cm2／s数量级，主要集中在10-11，cm2／s附近。嵌锂过程中。Du＋先出现极小值，然后出现极大值；脱锂过程中，阱先出现极大值，然后出现极小值。在同一电位下，充电过程（脱锂）的锂离子扩散系数大于放电过程（嵌锂）的锂离子扩散系数。

Nanostructured Li4TisO12 was used as a cathode material for the study. The chemical diffusion coefficient of Li-ion in Li4TisO12 was measured by potentiostatic intermittent titration technique （Pll-r） method and Li＋ diffusion behavior in nano Li4TisO12 was analyzed during the process of charging and discharging. The result shows that the diffusion coefficient of lithium ion in active material ranges from 10-~2 to 10-~~ cm2/s, and mainly concentrates in 10-＂ cm2/s. In the process of Li~ deintercalation, the diffusion coefficient comes to the minimum firstly, and then rises to a great value. While in the process of Li~ intercalation, the maximum comes first, and then decreases to a minimum. At the same potential, the charging process （lithium intercalation） of lithium ion exhibits a higher diffusion coefficient than the discharging process.