Development of All-Solid-State Batteries and Fuel Cells Utilizing the Material Technology of Multilayer Ceramic Capacitors

Abstract

Background and Aims: The push for a decarbonized society has intensified research into energy storage and generation technologies. This paper explores the application of Multilayer Ceramic Capacitor (MLCC) technology—a core technology of TAIYO YUDEN CO., LTD—to the development of advanced energy devices. MLCCs are miniaturized, high-capacity capacitors constructed by alternately stacking thin dielectric ceramic layers of BaTiO₃ (barium titanate) and Ni metal layers, followed by co-firing. This study focuses on enhancing BaTiO₃ powder properties for producing thin dielectric layers and applying this knowledge to the development of oxide-based all-solid-state batteries (ASSBs) and metal-supported solid oxide fuel cells (MS-SOFCs). The research aims to leverage MLCC technology to achieve the miniaturization and efficiency required for these next-generation energy devices.

Methods and Results: The study began with improving the solid-state synthesis of BaTiO₃, essential for achieving the thin dielectric layers needed in MLCCs. The reaction mechanism was investigated using fine BaCO₃ and TiO₂ powders, revealing that BaTiO₃ formation initiates at the contact points between the two materials, followed by Ba ion diffusion into TiO₂. By optimizing the particle size and homogeneity of the reaction mixture, the team successfully synthesized highly crystalline BaTiO₃ particles. These findings were then applied to the synthesis of battery materials, focusing on achieving a uniform dispersion of fine particles, essential for the thin-layer construction in both ASSBs and MS-SOFCs. The study demonstrated that using MLCC-based processing techniques—such as tape casting, stacking, and co-firing—enabled the production of all-solid-state batteries and SOFCs with promising performance characteristics.

Conclusions (Outlooks): The research highlights the potential of MLCC technology to drive advancements in energy device miniaturization and efficiency. The enhanced solid-state synthesis of BaTiO₃ and its application to battery materials underscore the feasibility of developing compact, high-performance energy devices. Future work will focus on further refining these materials and processing techniques, potentially leading to the commercialization of MLCC-based all-solid-state batteries and SOFCs. The success of this approach could contribute significantly to the development of sustainable energy technologies, aligning with global efforts toward decarbonization.