This dissertation discusses lead-free materials for electrocaloric solid-state cooling as a promising alternative to conventional vapor-compression technique, offering higher energy efficiency and environmentally friendly operation. However, electrocaloric systems have not yet been commercialized and are mainly demonstrated in prototypes, typically based on lead-containing materials. In order to comply with environmental regulations and enable sustainable device development, the design of lead-free electrocaloric materials is essential.
To fabricate multilayer ceramic components based on modified barium titanate, different sintering aids, grain growth inhibitors, and hydrothermal synthesis were systematically investigated to reduce sintering temperature and grain size. The effects of microstructure on the electrical properties, dielectric strength, and electrocaloric performance were also studied. The resulting lead-free multilayer ceramics with an average grain size of 1.7 µm achieved electrocaloric temperature changes of 1.4 K under an electric field change of 30 V/µm, and represent the most promising candidates for lead-free electrocaloric cooling devices.
Alexander Michaelis
lead-free materials electrocaloric grain growth inhibitors hydrothermal synthesis multilayer ceramic components Materialwissenschaftler