Optical fluorescence microscopy is shown to enable both high spatial and temporal resolution of redox-dependent fluorescence in flowing electrolytes. We report the use of fluorescence microscopy coupled with electrochemistry to directly observe the reaction and transport of redox-active quinones within porous carbon electrodes in operando. We observe surprising electrolyte channeling features within several porous electrodes, leading to spatially distinguishable advection-dominated and diffusion-dominated regions. These results challenge the common assumption that transport in porous electrodes can be approximated by a homogeneous Darcy-like permeability, particularly at the length scales relevant to many electrochemical systems such as redox flow batteries. This work presents a new platform to provide highly resolved spatial and temporal insight into electrolyte reactions and transport behavior within porous electrodes.

光学荧光显微镜显示出能够在流动的电解质中实现高空间和时间分辨率的氧化还原依赖性荧光。我们报道了使用耦合到电化学荧光显微镜直接观察多孔碳电极内的反应和氧化还原活性的醌运输中operando。我们在几个多孔电极中观察到令人惊讶的电解质通道特征，从而导致在空间上可区分的以平流为主和以扩散为主的区域。这些结果挑战了通常的假设，即多孔电极中的传输可以通过均匀的达西样渗透率来近似，特别是在与许多电化学系统（例如氧化还原液流电池）相关的长度尺度上。这项工作提出了一个新的平台，可以提供高度解析的时空洞察，以了解多孔电极内的电解质反应和传输行为。