Abstract
Steam electrolysers are a key technology for high-efficiency hydrogen production, offering superior thermodynamic performance compared with liquid-water electrolysis when operated at elevated temperatures. Despite these advantages, their wider deployment remains constrained by manufacturing complexity, component cost, and stringent processing requirements for ceramic membranes, electrodes, and interconnect-related components. This mini-review provides a comprehensive assessment of fabrication strategies relevant to steam-electrolyser manufacturing, encompassing compression-based forming, colloidal processing, fibre- and ink-based deposition techniques, as well as physical vapour deposition. Particular attention is given to how electrode architecture, cell geometry, and interfacial compatibility influence viable processing routes and manufacturability, rather than device operation at the single-cell level. Emphasis is placed on solid-state ceramic membranes and electrodes based on gadolinium-doped ceria (GDC) and yttria-stabilised zirconia (YSZ), which remain central to current and emerging steam-electrolyser technologies. Because most scalable fabrication routes ultimately depend on controlled densification and microstructural optimisation of polycrystalline ceramics, the review critically examines low-temperature sintering mechanisms, including grain-boundary-activated densification, transient liquid-phase formation, and nano-powder engineering. Recent advances in single- and multi-element sintering aids are discussed, with co-doping strategies shown to reduce densification temperatures by several hundred degrees while preserving ionic conductivity and long-term stability. A quantitative techno-environmental analysis further demonstrates that reducing electrolyte sintering temperatures from 1400 °C to 650–950 °C can lower energy consumption by 30–55 %, reduce fabrication costs, and significantly decrease CO₂ emissions associated with manufacturing. By integrating fabrication methodologies with low-temperature processing chemistry in a steam-electrolysis–relevant context, this review highlights the key materials–process interactions governing manufacturability and identifies future research directions for scalable, durable, and economically competitive steam-electrolyser technologies