Diffusion coefficients of lithium ions during intercalation into graphite derived from the simultaneous measurements and modeling of electrochemical impedance and potentiostatic intermittent titration characteristics of thin graphite electrodes
Diffusion coefficients of lithium ions during intercalation into graphite derived from the simultaneous measurements and modeling of electrochemical impedance and potentiostatic intermittent titration characteristics of thin graphite electrodes
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DOI：
10.1021/jp9701911
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发表时间：
1997-06-05
影响因子：
3.3
通讯作者：
Aurbach, D
中科院分区：
文献类型：
--
作者：
Levi, MD;Aurbach, D
使用恒电位间歇滴定（PITT）和阻抗谱（EIS）研究了电化学插层过程中锂向石墨中的固态扩散。基于两种方法计算了作为插层水平 (X) 和电极电势 (E) 函数的扩散系数 (D)，并给出了相似的结果。发现 D 与 X 或 E 图是非单调的，在相同电位处具有三个明显的最小值，其中这些系统的循环伏安法显示与锂-石墨嵌入阶段之间的相变相关的峰。研究发现，这些电极的临界扩散长度与石墨颗粒沿其基面的尺寸有关，而不与电极厚度有关。根据插层过程的性质讨论了 D 对 X 和 E 的峰状依赖性的原因。
The solid state diffusion of Lithium into graphite during electrochemical intercalation processes was investigated using potentiostatic intermittent titration (PITT) and impedance spectroscopy (EIS). The diffusion coefficient (D) as a function of the intercalation level (X) and the electrode potential (E) was calculated on the basis of both methods and gave similar results. The D vs X or E plots were found to be nonmonotonous, with three pronounced minima at the same potentials in which the cyclic voltammetry of these systems shows the peaks related to the phase transition between the Lithium-graphite intercalation stages. It was found that the critical diffusion length for these electrodes relates to the graphite particles' dimensions along their basal planes and not to the electrode thickness. The reason for the peaklike dependence of the D on X and E is discussed in light of the nature of the intercalation processes.