Materials challenges on the path to gigatonne CO2 electrolysis

CO2 electroreduction (CO2E) is one promising strategy towards decarbonization, offering a path to produce widely used chemicals such as fuels or manufacturing feedstocks using renewable energy and waste CO2 (as opposed to fossil fuels). CO2E performance at the laboratory scale is advancing quickly, including ongoing scale-up and industrialization efforts. To address global CO2 emissions (similar to 37 Gt per year), CO2 electrolysers and components, as well as upstream and downstream associated technologies, must be deployed at the gigawatt scale. This entails considerable challenges beyond performance, such as resource availability, deployment readability and end-of-life system management, which are today overlooked. In this Review, we analyse the impending resource challenges as CO2E deployment approaches gigatonne scale, considering a life cycle assessment focused on the associated materials and their corresponding global warming impact. We identify scalability bottlenecks related to membranes, electrode supports and anode materials, among others, and discuss the need for more stable carbon-efficient systems and materials recycling strategies. We conclude with potential approaches to rationally design materials towards sustainable CO2 capture and electrolysis at the gigatonne scale.