Quantifying the impact of viscosity on mass-transfer coefficients in redox flow batteries
Quantifying the impact of viscosity on mass-transfer coefficients in redox flow batteries
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DOI：
10.1016/j.jpowsour.2018.07.046
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发表时间：
2018-09-30
影响因子：
9.2
通讯作者：
Brushett, Fikile R.
中科院分区：
文献类型：
--
作者：
Barton, John L.;Milshtein, Jarrod D.;Brushett, Fikile R.
在这里，一个模型氧化还原活性电解质（RAE）的充分特点是在其传输特性，和随后的流动电池极化实验，使提取的传质系数。具体而言，流量和电解质粘度的实验操作与流动池中的1-D极化模型相结合，以量化作为这些材料和操作参数的函数的传质系数。流通和交叉流场被用来开发无量纲的相关性，描述作为RAE属性的函数的传质速率。实验结果和拟合的模型参数说明和量化的限制电流和传质系数作为电解质的速度和粘度的函数的变化。根据Peclet（Pe）和施密特（Sc）数，得出的舍伍德数（Sh）的幂律关系式分别为：流通流场和叉指流场的Sh = 0.0040 Pe（0.75）Sc（-0.24）和Sh = 0.018 Pe（0.68）Sc（-0.18）。这些相关性提供了高性能液流电池架构内的传质系数的定量估计，作为几何形状和RAE特性的函数，从而能够在未来的RAE开发活动中进行前端筛选，以及为潜在的氧化还原液流电池（RFB）进行性能基准测试。
Here, a model redox-active electrolyte (RAE) is fully characterized in terms of its transport properties, and subsequent flow cell polarization experiments enable extraction of mass-transfer coefficients. Specifically, experimental manipulation of flow rate and electrolyte viscosity are coupled with a 1-D polarization model in a flow cell to quantify the mass-transfer coefficients as a function of these material and operating parameters. Both flow-through and interdigitated flow fields are used to develop dimensionless correlations that describe mass transfer rates as a function of RAE properties. Experimental results and fitted model parameters illustrate and quantify the changes in limiting current and mass-transfer coefficient as a function of electrolyte velocity and viscosity. The resulting power-law correlations for the Sherwood (Sh) number, in terms of the Peclet (Pe) and Schmidt (Sc) numbers, are Sh = 0.0040Pe(0.75)Sc(-0.24) and Sh = 0.018Pe(0.68)Sc(-0.18) for the flow-through and inter digitated flow fields, respectively. These correlations provide quantitative estimates of mass-transfer coefficients within high-performance flow cell architectures as a function of geometry and RAE properties, enabling front-end screening in future RAE development campaigns, as well as performance benchmarking for potential redox flow batteries (RFBs).