High Energy Storage Efficiency and Electrocaloric Effect in Pb-Free Ba 0.85 Ca 0.15 Hf 0.10 Ti 0.90 O 3 Ceramics for Sustainable Green Energy Applications

• Published in: ECS transactions 2022-04, Vol.107 (1), p.19969-19978
• Main Authors: Nandan, Revati, Kumar, Sanjeev, Negi, Nainjeet Singh
• Format: Article
• Language: English
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/10701.19969ecst

In this work, Pb-free Ba 0.85 Ca 0.15 Hf 0.10 Ti 0.90 O 3 (BCHT) ferroelectric ceramic was synthesized via the sol-gel method and its structural, dielectric, ferroelectric, electrocaloric, and energy storage characteristics have been investigated under a low electric field of 20 kV/cm. The Rietveld refinement of XRD patterns shows good agreement with the co-existence of two phases tetragonal (P4mm) and cubic (Pm3m), with each phase contribution of 58 and 42% respectively. A volumetric porosity of around 11.5% is observed. The electrocaloric temperature change ΔT and entropy change ΔS have been estimated by an indirect approach using Maxwell relations. The room temperature value of – ΔS and ΔT are 0.207 J/Kg.K and 0.157 K respectively and a wide temperature span of 50K was observed. The room temperature observed enhanced total energy density, recoverable energy density, and energy storage efficiency were 84.43 mJ/cm 3 , 64.38 mJ/cm 3 , and 76.25 % respectively. The maximum energy storage efficiency of 85.03% was observed at 80 o C. The Pb-free BCHT ceramic is a promising candidate for eco-friendly cooling and energy storage technology.