Storage is today the greatest challenge facing energy engineers. The cost of solar and wind energy has plummeted, and triggered a revolutionary decentralization process in the power generation sector. This ongoing transformation calls for improved energy storage technologies. Owing to the intermittent and unpredictive nature of renewables, whose penetration on the electric grid is growing fast, the need has emerged for both short and long-term electricity storage. Two electrochemical technologies, both based on the use of solid state ionic conductors, that can tackle this problem are lithium ion batteries (LIBs), for short-term storage; and solid oxide cells (SOCs) for seasonal storage. This thesis comprises three parts, addressing three key factors for the design and optimizati...[ Read more ]

Storage is today the greatest challenge facing energy engineers. The cost of solar and wind energy has plummeted, and triggered a revolutionary decentralization process in the power generation sector. This ongoing transformation calls for improved energy storage technologies. Owing to the intermittent and unpredictive nature of renewables, whose penetration on the electric grid is growing fast, the need has emerged for both short and long-term electricity storage. Two electrochemical technologies, both based on the use of solid state ionic conductors, that can tackle this problem are lithium ion batteries (LIBs), for short-term storage; and solid oxide cells (SOCs) for seasonal storage. This thesis comprises three parts, addressing three key factors for the design and optimization of systems such as LIBs and SOCs, namely material catalytic performance and long-term stability, and fabrication and manufacturing. First, we study the influence of the fabrication parameters, such as deposition temperature and laser fluence, on the performance of Ta substituted Li_6.4La₃Zr₂O₁₂ (LLZO) thin films, a promising solid electrolyte for all solid LIB. Next, we investigate alternative methods to improve the long-term stability of La doped BaFeO_3-δ (BLF). This excellent SOCs’ material suffers from segregation of Ba to the surface, which hinders its high activity. First, we prepare thin films of BLF via Pulsed Laser Deposition (PLD), and either coat them with ZrO₂ via Atomic Layer Deposition (ALD) or co-doped them with Zr. Afterwards, we analyze the composition of the various films, with particular attention for the concentration of Ba via angle resolved XPS. Finally, we investigate the effects of niobium (Nb) substitution into PrBaCo₂O_5+δ (PBC), which is among the best materials for SOCs. Substituting Nb was reported to be beneficial both in terms of enhanced catalytic activity and stability. We synthesize the material containing different amounts of Nb, and characterize its structure and electro-catalytic performance.