Localised electrochemical impedance measurements of a polymer electrolyte fuel cell using a reference electrode array to give cathode-specific measurements and examine membrane hydration dynamics
Localised electrochemical impedance measurements of a polymer electrolyte fuel cell using a reference electrode array to give cathode-specific measurements and examine membrane hydration dynamics
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DOI：
10.1016/j.jpowsour.2018.02.022
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发表时间：
2018-04
影响因子：
9.2
通讯作者：
Erik Engebretsen;G. Hinds;Q. Meyer;T. Mason;E. Brightman;L. Castanheira;P. Shearing;D. Brett
中科院分区：
文献类型：
--
作者：
Erik Engebretsen;G. Hinds;Q. Meyer;T. Mason;E. Brightman;L. Castanheira;P. Shearing;D. Brett
聚合物电解质燃料电池定制诊断技术的进步继续为这些设备的内部操作提供独特的见解，并提高性能和耐用性。电流密度的局部测量已被证明在设计更好的燃料电池和确定最佳操作策略方面非常有用，电化学阻抗谱（EIS）现在通常用于去卷积燃料电池中的各种损耗。结合这两种技术提供了另一个维度的理解，但到目前为止，每一个局部的EIS一直基于2电极测量，包括阳极和阴极的响应。这项工作表明，一个参考电极阵列可以用来给个别电极特定的EIS响应，在这种情况下，阴极的重点是证明的approach.In此外，膜水合动力学研究下的电流负载步骤从开路电压。确定了一个三阶段的过程，与施加电流阶跃10 s后膜电阻的初始快速降低相关，随后是一个缓慢的斜坡至近似稳态，这是在250 s后实现的。这些结果支持以前发表的工作，已经看了膜溶胀动力学，并揭示膜水合/膜电阻是高度异质性的。
Advances in bespoke diagnostic techniques for polymer electrolyte fuel cells continue to provide unique insight into the internal operation of these devices and lead to improved performance and durability. Localised measurements of current density have proven to be extremely useful in designing better fuel cells and identifying optimal operating strategies, with electrochemical impedance spectroscopy (EIS) now routinely used to deconvolute the various losses in fuel cells. Combining the two techniques provides another dimension of understanding, but until now each localised EIS has been based on 2-electrode measurements, composed of both the anode and cathode responses. This work shows that a reference electrode array can be used to give individual electrode-specific EIS responses, in this case the cathode is focused on to demonstrate the approach.In addition, membrane hydration dynamics are studied under current load steps from open circuit voltage. A three-stage process is identified associated with an initial rapid reduction in membrane resistance after 10 s of applying a current step, followed by a slower ramp to approximately steady state, which was achieved after ∼250 s. These results support previously published work that has looked at membrane swelling dynamics and reveal that membrane hydration/membrane resistance is highly heterogeneous.