Ferner Kara J, Litster Shawn
Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
ACS Appl Energy Mater. 2024 Sep 6;7(18):8124-8135. doi: 10.1021/acsaem.4c01866. eCollection 2024 Sep 23.
To enable the greater installed capacity of proton exchange membrane water electrolysis (PEMWE) for clean hydrogen production, associated costs must be lowered while achieving high current density performance and durability. Scarce and expensive iridium (Ir) required for the oxygen evolution reaction (OER) is a large contributor to the overall cost, yet high loadings of Ir (1-2 mg cm) are currently needed in commercial systems to maintain sufficient activity, conductivity, and durability. To meet the aggressive targets for low Ir loadings, we introduce a composite anode approach using a conductive additive that is less expensive than Ir to facilitate robust, high-performance operation with low Ir loading by retaining electrode thickness and in-plane electrical conductivity. In this demonstration, we use platinum (Pt) black as the conductive additive given its high electrical conductivity, acid stability, and current price one-fifth that of Ir. Using a high-activity commercial Ir oxide (IrO ) catalyst, we present a 95% Ir loading reduction and 80% cost reduction of the anode catalyst materials while maintaining equal current density performance at a cell voltage of 1.8 V. Furthermore, we show enhanced stability of a composite anode compared to an IrO anode with loadings of 0.10 mg cm via accelerated stress test (AST) and postmortem imaging. With this approach, we show promising results toward lowering Ir loadings and material costs, addressing a significant barrier to the widespread adoption of PEMWE for clean hydrogen production.
为了提高质子交换膜水电解（PEMWE）制氢的装机容量，必须在实现高电流密度性能和耐久性的同时降低相关成本。析氧反应（OER）所需的稀缺且昂贵的铱（Ir）是总成本的一个重要组成部分，然而目前商业系统中仍需要高负载量的Ir（1-2 mg/cm²）来维持足够的活性、导电性和耐久性。为了实现低Ir负载量的激进目标，我们引入了一种复合阳极方法，使用一种比Ir便宜的导电添加剂，通过保持电极厚度和平面内电导率，以促进低Ir负载量下的稳健、高性能运行。在本演示中，我们使用铂（Pt）黑作为导电添加剂，因为它具有高电导率、酸稳定性，且当前价格仅为Ir的五分之一。使用高活性的商业氧化铱（IrO₂）催化剂，我们在电池电压为1.8 V时，将阳极催化剂材料的Ir负载量降低了95%，成本降低了80%，同时保持了相同的电流密度性能。此外，通过加速应力测试（AST）和死后成像，我们表明与负载量为0.10 mg/cm²的IrO₂阳极相比，复合阳极的稳定性得到了增强。通过这种方法，我们在降低Ir负载量和材料成本方面展示了有前景的结果，解决了PEMWE广泛应用于清洁制氢的一个重大障碍。
