Berlinger Sarah A, Chowdhury Anamika, Van Cleve Tim, He Aaron, Dagan Nicholas, Neyerlin Kenneth C, McCloskey Bryan D, Radke Clayton J, Weber Adam Z
Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720 United States.
Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States.
ACS Appl Mater Interfaces. 2022 Aug 17;14(32):36731-36740. doi: 10.1021/acsami.2c10499. Epub 2022 Aug 2.
A variety of electrochemical energy conversion technologies, including fuel cells, rely on solution-processing techniques (via inks) to form their catalyst layers (CLs). The CLs are heterogeneous structures, often with uneven ion-conducting polymer (ionomer) coverage and underutilized catalysts. Various platinum-supported-on-carbon colloidal catalyst particles are used, but little is known about how or why changing the primary particle loading (PPL, or the weight fraction of platinum of the carbon-platinum catalyst particles) impacts performance. By investigating the CL gas-transport resistance and zeta (ζ)-potentials of the corresponding inks as a function of PPL, a direct correlation between the CL high current density performance and ink ζ-potential is observed. This correlation stems from likely changes in ionomer distributions and catalyst-particle agglomeration as a function of PPL, as revealed by pH, ζ-potential, and impedance measurements. These findings are critical to unraveling the ionomer distribution heterogeneity in ink-based CLs and enabling enhanced Pt utilization and improved device performance for fuel cells and related electrochemical devices.
包括燃料电池在内的多种电化学能量转换技术都依赖溶液处理技术（通过油墨）来形成其催化剂层（CLs）。催化剂层是异质结构，通常具有不均匀的离子导电聚合物（离聚物）覆盖和未充分利用的催化剂。使用了各种负载在碳上的铂胶体催化剂颗粒，但对于改变初级颗粒负载量（PPL，即碳 - 铂催化剂颗粒中铂的重量分数）如何或为何会影响性能却知之甚少。通过研究相应油墨的CL气体传输阻力和zeta（ζ）电位随PPL的变化，观察到CL高电流密度性能与油墨ζ电位之间存在直接相关性。这种相关性源于离聚物分布和催化剂颗粒团聚可能随PPL的变化，pH、ζ电位和阻抗测量揭示了这一点。这些发现对于揭示基于油墨的CLs中离聚物分布的异质性以及提高燃料电池和相关电化学装置的铂利用率和改善器件性能至关重要。
