Multilayer Ceramics for Electrocaloric Cooling Applications

Abstract

The electrocaloric effect of 0.92 Pb(Mg1/3Nb2/3)O3‐0.08 PbTiO3 (PMN‐8 PT) bulk ceramics and multilayer ceramic (MLC) structures is reported. The results are compared to lead‐free, barium‐titanate‐based materials. Phase transition temperature and electrocaloric temperature change could be altered by targeted doping and this is discussed with the help of dielectric and electrocaloric measurements. By reduction of single layer thickness in MLCs, electrical loads and thus electrocaloric temperature changes of PMN‐8 PT based multilayers could be increased. Simulations that outline the intrinsic cooling performance of electrocaloric MLC components in dependence of the multilayer design and operation frequency for two different modes of heat transfer are presented. The performance of the fabricated MLC layout for a driving frequency of 1 Hz is discussed in detail and an optimum layout by varying of design parameters derived. Additionally, the effect of driving frequency on the electrocaloric cooling power is investigated.

Electrocaloric Performance of Multilayer Ceramic Chips: Effect of Geometric Structure Induced Internal Stress

“…Subsequently, high-performance heat pumps based on electrocaloric phenomenon were introduced using PST multilayer capacitors. , These results emphasize that high heat flow and big temperature drop are both required for developing practical applications. The multilayer ceramic capacitors (MLCCs) are attractive because they seem to satisfy these requirements. , MLCCs combine high breakdown field due to the thin ceramic layer thickness and a high surface/volume ratio, which favors the efficient heat transfer. ,, The efficiency of heat transfer is also related to the high thermal conductivity of the interdigitated metallic electrodes . The interdigitated multilayer comprising of dielectric layers and electrode layers has distinguishing structural/microstructural features that are different from bulk and thin films and needs to be investigated in terms of their influence on the EC performance.…”

“…15,19 MLCCs combine high breakdown field due to the thin ceramic layer thickness and a high surface/volume ratio, which favors the efficient heat transfer. 4,20,21 The efficiency of heat transfer is also related to the high thermal conductivity of the interdigitated metallic electrodes. 19 The interdigitated multilayer comprising of dielectric layers and electrode layers has distinguishing structural/microstructural features that are different from bulk and thin films and needs to be investigated in terms of their influence on the EC performance.…”

Enhancing Electrocaloric Heat Pump Performance by Over 99% Efficient Power Converters and Offset Fields

“…The state levels (dashed) are extracted with the histogram method. (raw data, not corrected by kT) [2], the actual internal material ∆T AD,MAX (dotted lines) is higher than the measured values (solid) by a ratio of k T . This ratio is due to ratio of the thickness and materials of the electrodes compared to the active EC layers and can be reduced.…”

“…The electrodes of the MLCC component add additional mass which reduces the effective externally observed temperature change. For a typical MLCC with N electrocaloric ceramic layers between 2 outer and N − 1 inner electrodes, the transformation coefficient [2]…”

Layered structure of alumina/graphene-augmented-inorganic-nanofibers with directional electrical conductivity

“…Similarly, in synthetic materials, addition of new functionalities such as an electro-conductive layer may allow for a directional materials response, i.e. high anisotropy in thermal and electrical conduction which opens venues for diverse applications including heat management [4], electro calorific effect [5], electromagnetic interference (EMI) shielding [6], multilayer ceramic capacitors, etc.…”