(Invited) Recycling Considerations for PEM Electrolysis Materials

Abstract

Hydrogen from water electrolysis has been touted as a green alternative to displace existing hydrogen feedstocks derived from fossil fuels. Proton exchange membrane (PEM)-based electrolyzers are one commercial pathway with the potential to meet the cost, performance, and application requirements. However, to truly represent a sustainable pathway, the production lifecycle needs to be considered, especially related to critical materials such as catalysts and polyfluorinated alkyl substances (PFAS) such as Nafion™ and other polyfluorosulfonic acid (PFSA) membranes. PFAS are beginning to be regulated globally, with a goal of phasing them out where possible. Recycling programs for the polymers used in electrolyzers can assist in keeping them exempt from PFAS regulations, due to the minimized environmental impact and lack of related emissions. In addition, PEM electrolyzers use a significant amount of platinum group metals, including iridium, one of the scarcest naturally occurring elements. Addressing these issues through recycling of key components is an important part of large scale commercialization and deployment.The need for recycling is based on both scarcity and environmental sustainability considerations. Customers are starting to ask more questions about supplier philosophy and documentation of environmental practices. Many manufacturing companies are certified to the ISO9001 quality standard, but many are now looking to be also certified to ISO14001, the environmental standard. ISO14001 represents certification to a group of standards designed to minimize a company’s negative impact on the environment. These standards show a voluntary commitment to environmental regulation and can give companies a competitive advantage when dealing with customers concerned about the environment. While recycling of any particular chemicals is not specifically required by ISO14001, the standards include lifecycle assessments, integration of environmental aspects into product design, reduction of greenhouse gas emissions, and related topics where recycling would have positive impact on the metrics.For platinum group metals, recycling is required to meet the projected capacity demands for electrolyzers before 2050. Many analyses are projecting gigawatt annual capacities for electrolysis within the next 10 years, and in fact several European countries have already made commitments to site part of this capacity. With 7-10 year stack life, recovering stacks to recycle the platinum group metals is important to sustain the existing fielded capacity as more electrolyzers are deployed. Recycling other components such as titanium, stainless steel, and fluoropolymers provides some additional value stream from reclamation as well. For maximum benefit, material collection methods need to be set up within the manufacturing facility, to capture waste materials and scrap, as well as through the field population, so that systems no longer being operated can be reclaimed for materials. This talk will cover some of the business considerations for effective recycling, as well as current practices.