Song Juhyun, Bazant Martin Z
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Phys Rev Lett. 2018 Mar 16;120(11):116001. doi: 10.1103/PhysRevLett.120.116001.
We develop a mathematical framework to analyze electrochemical impedance spectra in terms of a distribution of diffusion times (DDT) for a parallel array of random finite-length Warburg (diffusion) or Gerischer (reaction-diffusion) circuit elements. A robust DDT inversion method is presented based on complex nonlinear least squares regression with Tikhonov regularization and illustrated for three cases of nanostructured electrodes for energy conversion: (i) a carbon nanotube supercapacitor, (ii) a silicon nanowire Li-ion battery, and (iii) a porous-carbon vanadium flow battery. The results demonstrate the feasibility of nondestructive "impedance imaging" to infer microstructural statistics of random, heterogeneous materials.
我们开发了一个数学框架，用于根据随机有限长度的Warburg（扩散）或Gerischer（反应扩散）电路元件的并联阵列的扩散时间分布（DDT）来分析电化学阻抗谱。提出了一种基于带Tikhonov正则化的复非线性最小二乘回归的稳健DDT反演方法，并针对三种用于能量转换的纳米结构电极情况进行了说明：（i）碳纳米管超级电容器，（ii）硅纳米线锂离子电池，以及（iii）多孔碳钒液流电池。结果证明了无损“阻抗成像”以推断随机、异质材料的微观结构统计信息的可行性。
