Charge transfer kinetics at the solid-solid interface in porous electrodes
Charge transfer kinetics at the solid-solid interface in porous electrodes
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DOI：
10.1038/ncomms4585
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发表时间：
2014-04-01
影响因子：
16.6
通讯作者：
Bazant, Martin Z.
中科院分区：
文献类型：
--
作者：
Bai, Peng;Bazant, Martin Z.
界面电荷转移被广泛认为服从Butler-Volmer动力学。对于某些液固界面，Marcus-Hush-Chidsey理论更准确且更具预测性，但尚未应用于多孔电极。在这里，我们报告了一个简单的方法来提取碳涂层LiFePO 4多孔电极的电荷转移速率从计时电流实验，获得曲线塔菲尔图，矛盾的Butler-Volmer方程，但适合马库斯-Hush-Chidsey预测在一定的温度范围内。拟合重组能匹配的玻恩溶剂化能的电子转移从碳到铁的氧化还原位点。因此，动力学的限制，在固-固（碳-LixFePO 4）界面的电子转移，而不是在液-固界面的离子转移，如前所述。所提出的实验方法概括了Chidsey的相变颗粒和多孔电极的方法，结果表明，需要将马库斯动力学建模电池和其他电化学系统。
Interfacial charge transfer is widely assumed to obey the Butler-Volmer kinetics. For certain liquid-solid interfaces, the Marcus-Hush-Chidsey theory is more accurate and predictive, but it has not been applied to porous electrodes. Here we report a simple method to extract the charge transfer rates in carbon-coated LiFePO4 porous electrodes from chronoamperometry experiments, obtaining curved Tafel plots that contradict the Butler-Volmer equation but fit the Marcus-Hush-Chidsey prediction over a range of temperatures. The fitted reorganization energy matches the Born solvation energy for electron transfer from carbon to the iron redox site. The kinetics are thus limited by electron transfer at the solid-solid (carbon-LixFePO4) interface rather than by ion transfer at the liquid-solid interface, as previously assumed. The proposed experimental method generalizes Chidsey's method for phase-transforming particles and porous electrodes, and the results show the need to incorporate Marcus kinetics in modelling batteries and other electrochemical systems.