Recently, it has been demonstrated that the application of additive manufacturing (AM) technologies for functional ceramics fabrication, especially to SOC production, leads to significant improvement of the process. AM represents freedom of design that allows to enhance the performance of the SOC-based device and to increase manufacturing productiveness, while the waste material is reduced. As a result, a one-step printed monolithic SOFC stack could be produced combining different AM technologies in a single printing process. For this purpose, hybrid 3D printing technology which combines stereolithography and robocasting has been developed. Thus, the technique uses 8YSZ for the electrolyte fabrication by stereolithography and deposition of electrodes and interconnectors by robocasting. The elaborated hybrid multimaterial 3D printing technology renders possible complete SOC stack fabrication as a single-step process. Complete fully printed SOFC cells, their co-sintering process, and their characterization are here presented and discussed.

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The development of alternative sources for electric power generation and energy storage to meet the growing demand and ensuring environmental sustainability for the next decades is still being a challenge for the scientific community. In this context, fuel cells are of great interest in enabling sustainable generation of electricity, being highly efficient and being a reliable, efficient and safe technology during its operation. Fuel cells are electrochemical devices that directly convert chemical energy into electrical energy and heat by continuously feeding a fuel and an oxidant, and can also use surpluses of energy to reduce water to hydrogen as a chemical storage route when working on reverse mode. These devices are made up of two electrodes (fuel electrode and oxygen electrode) separated by an electrolyte. It has been shown that the use of additive manufacturing (AM) technologies combined with ceramic fabrication techniques to optimize the microstructures and geometries of the SOC devices enhance its performance and reliability. New printable formulations for ceramic pastes have been developed for electrolytes in order to enhance the active area of reaction. Among different strategies to improve the performance, the use of composite electrodes base on porous scaffold of the ionic conductor phase to be infiltrated by the catalytic active phase is widely used. With the advance of the AM technology, 8YSZ electrolytes and scaffolds with different configurations can be also fabricated by 3D printing method. In this present work, we aim to fabricate an innovative and complex structure for YSZ electrodes with dense and porous parts and optimize the fabrication parameters for different 3D-printing process to obtain enhanced features of the ceramic supports that will be applied for SOC. Focusing on optimize the 3D processing of combined porous and dense structures for SOFC/SOECs, dense (δ>95%) monolithic gas-tight YSZ thin electrolytes supported by porous scaffolds on both sides will be fabricated for later functionalization by infiltration of the electrodes. The fabrication of the porous dense porous electrolyte will be generated by: porosity integrated by the CAD design, generation of porosity by development of new ceramic pastes and tuning of the printing parameters.

Nowadays, renewable energy increases its contribution to the present energy scenario. In this regard, the implementation of energy storage and sources as the electrolysers and fuel cells gives the opportunity to transform the surplus of renewable energy to the form of hydrogen, by water electrolysis and the use of this hydrogen as a fuel for energy generation by the reverse mode of the same devices, in the so-called power to gas and gas to power routes. Among the different technologies of fuel cells and electrolysers, the high temperature technology based on ceramic solid oxides presents the best efficiencies. However, the fabrication of this devices implies several manufacturing procedures and multiple intermediate steps of fabrications, such as tape-casting, screen-printing, annealing, manual stacking, joining, sealing, etc. As a result, the SOC production process becomes more expensive and time-consuming. Recently, it has been demonstrated that the application of additive manufacturing (AM) technologies for functional ceramics fabrication, specially to SOC production, leads to significant improvement of the process. AM represents freedom of design, that allows to enhance the performance of the SOC-based device, an increase of manufacturing speed and productiveness, while the waste material is reduced. As a final result, one-step printed monolithic SOFC stack could be produced combining different AM technologies in a single printing process. For this purpose, hybrid 3D printing technology which combines stereolithography (SLA) and robocasting (direct ink writing, DIW) has been developed. Thus, the technique uses 8YSZ for the electrolyte fabrication by SLA and deposition of electrodes and interconnectors by DIW. The elaborated hybrid multimaterial 3D printing technology renders possible complete SOC stack fabrication as a single-step process. Complete fully printed SOFC cells, their co-sintering process and their characterization are here presented while the advantages and limitations of the fabrication process are discussed.