Large Room-Temperature Electrocaloric Response Realized in Potassium-Sodium Niobate by a Relaxor Enhancement Effect and Multilayer Ceramic Construct

The development of high-performance electrocaloric (EC) materials is crucial for solid-state refrigeration applied in micro-electromechanical systems. Herein, a large room-temperature EC response is realized in (1 – x)(K0.49Na0.49Li0.02)(Nb0.8Ta0.2)O3–xCaZrO3 (KNLNT–xCZ) benefiting from a relaxor enhancement effect and multilayer ceramic construct. The relaxor enhancement effect is because the long-range order is broken by adding CaZrO3, which is in favor of enhancing the temperature change (ΔT) and broadening the temperature span (Tspan) at room temperature. A ΔT of 0.48 K in the KNLNT–12CZ ceramic is ∼5 times higher than that in the KNLNT–8CZ ceramic at 30 °C. KNLNT–12CZ also exhibits good temperature stability, and the Tspan is up to 65 K. In addition, the multilayer ceramic construct improves the breakdown electric field (Eb) through diminishing defects, leading to a booming ΔT of 3.2 K at 30 °C under 250 kV cm–1 via a direct measurement. The work proposes an avenue for developing high-performance EC materials with a large EC response and broad Tspan in solid-state refrigeration.