Vicente Nuria, Haro Marta, Garcia-Belmonte Germà
Institute of Advanced Materials (INAM), Universitat Jaume I, ES-12006 Castelló, Spain.
Chem Commun (Camb). 2018 Jan 25;54(9):1025-1040. doi: 10.1039/c7cc08373d.
Electrochemical impedance spectroscopy is a widely employed technique probing kinetic limitations in the charging of battery electrodes. Hindrance mechanisms locate at the interfaces between the active material and the electrolyte, and in the bulk of the reacting compound. Rate-limiting mechanisms are viewed as resistive circuit elements and can be extracted using standard impedance analyzers. Classical impedance models consider charge transport, mainly ion diffusion as slower carrier, as the principal kinetic limitation impeding full electrode charging. This is indeed the case for many technologically relevant battery compounds. In other instances, instead of being diffusion-limited, electrodes may undergo charging limitation caused by the kinetics of the reduction reaction itself. Specific impedance models for reaction-limited mechanisms are summarized here and proved for relevant electrode compounds, in particular for conversion or alloying electrodes in which Li intake produces a full rearrangement of the lattice structure with significant atomic displacement.
电化学阻抗谱是一种广泛应用的技术，用于探究电池电极充电过程中的动力学限制。阻碍机制位于活性材料与电解质之间的界面以及反应化合物的本体中。限速机制被视为电阻性电路元件，可以使用标准阻抗分析仪进行提取。经典阻抗模型认为电荷传输（主要是离子扩散作为较慢的载流子）是阻碍电极完全充电的主要动力学限制。对于许多具有技术相关性的电池化合物来说确实如此。在其他情况下，电极可能不是受扩散限制，而是由还原反应本身的动力学导致充电受限。本文总结了反应受限机制的特定阻抗模型，并针对相关电极化合物进行了验证，特别是对于锂嵌入会导致晶格结构完全重排且原子位移显著的转化或合金化电极。
