Coexistence of negative and positive electrocaloric effect in lead-free 0.9(K0.5Na0.5)NbO3 - 0.1SrTiO3 nanocrystalline ceramics

Abstract

The coexistence of negative and positive electrocaloric effect have been experimentally demonstrated in lead-free 0.9(K0.5Na0.5)NbO3 - 0.1SrTiO3 nanocrystalline ceramics using an indirect thermodynamic method. The electrocaloric response of −0.85K at 276K and 0.43K at 330K were calculated at 40kV/cm. The corresponding electrocaloric coefficient were estimated to be −0.24×10−7K·mV−1 and 0.7×10−7K·mV−1 at 273K and 333K, respectively. A large electrical storage energy density 1.46J/cm3 were achieved. The results indicate that materials possess a huge potential for electrocaloric refrigeration as a micro-cooler and energy storage capacity for electronic devices.