What is decal transfer technology?
Decal transfer technology is a manufacturing method employed to create the catalyst-coated membrane (CCM) found in fuel cells and electrolysers. The MEA comprises several layers, including a fluoropolymer electrolyte membrane situated between catalyst-coated electrodes (anode and cathode). The process consists of two main steps:
1. Applying the catalyst: In this initial step, catalyst ink or paste is applied to a substrate film. For optimal results, the substrate must possess high surface energy to ensure proper wettability; otherwise, the catalyst will form isolated droplets rather than spreading evenly.
2. Transferring the catalyst layer: The second step involves adhering the crystalline catalyst layer to the substrate, which is then pressed onto the membrane. After pressing, the substrate is peeled away, aiming for complete transfer without residual material. Achieving this requires a low surface energy on the substrate for effective release, creating a challenge as both high and low surface energies are needed for different steps of the process.
Versiv Composites aims to deliver high-quality solutions for producing catalytic layers for CCMs. Our DF100 5 mil substrate effectively meets both requirements: it has adequate surface energy for initial wettability while allowing for seamless transfer.
Environmental benefits of decal transfer technology
From an environmental perspective, decal transfer technology presents advantages over traditional spray coating methods. Spray coating can sometimes result in uneven catalyst application across the MEA, leading to performance inconsistencies. Additionally, it can potentially contribute to air pollution due to solvent use and restrict human activity in proximity during application.
In contrast, decal transfer allows for precise application of thinner catalyst layers compared to conventional methods. This not only conserves precious metals and reduces costs but also minimises resource usage – enhancing sustainability. The repeatability of the decal transfer process ensures uniformity across layers, resulting in consistent performance in fuel cells and electrolysers.
Moreover, high-quality substrates enable thinner catalyst layers without compromising performance. Inadequate adhesion from directly coated layers can lead to delamination or operational failures, jeopardising system integrity.
Cost efficiency and mould release
During cell stacking, components must easily release from moulds without leaving residual materials behind. This ease of release minimises downtime during MEA pressing, contributing to cost savings – a crucial factor when selecting renewable energy materials like Versiv’s CL4 and CF205.
Future potential of decal substrates and catalyst inks
Despite its existing advantages, there is still room for improvement within decal transfer technology. Future advancements may focus on developing substrates with optimised surface properties that enhance both wettability and transfer efficiency. Innovations in catalyst formulations could yield inks with better adhesion, conductivity, and durability – further reinforcing the benefits of this method.
Direct coating method (DCM)
In addition to decal transfer technology, direct coating methods (DCM) should be considered. DCM includes two main forms:
1. Directly coating the membrane (spray)
2. Decal transfer with liquid membrane instead of membrane foil: This method involves using a substrate (e.g., DF100 material), followed by electrode application (anode or cathode), liquid membrane casting, and subsequent electrode application before peeling off the substrate.
Given this context, decal transfer technology offers notable advantages over direct coating methods regarding precision, material efficiency, environmental impact, adhesion strength, and scalability. Thinner membranes enhance fuel cell efficiency while reducing costs associated with precious metals and minimising resource consumption – contributing to sustainability in clean technology development.
In summary, decal transfer technology stands out as a preferred choice for producing high-performance CCMs in fuel cell and electrolyser applications, ultimately fostering improved sustainability within clean technology initiatives.
