A Superparaelectric State in Relaxor Ferroelectric (Sr,Bi)TiO 3 -Bi(Mg,Ti)O 3 -Modified BaTiO 3 Ceramics to Achieve High Energy Storage Performance

• Published in: Materials Vol. 17; no. 2
• Main Authors: Yoo, Il-Ryeol, Choi, Seong-Hui, Park, Je-Yeon, Kim, Min-Seok, Yadav, Arun Kumar, Cho, Kyung-Hoon
• Format: Journal Article
• Language: English
• Published: Switzerland 15-01-2024
• Subjects: energy storage density; BaTiO3; superparaelectric; relaxor ferroelectric; dielectric ceramic capacitor
• ISSN: 1996-1944; 1996-1944

Dielectric ceramic capacitors are highly regarded for their rapid charge-discharge, high power density, and cyclability in various advanced applications. However, their relatively low energy storage density has prompted intensive research aiming at developing materials with a higher energy density. To enhance energy storage properties, research has focused on modifying ferroelectric materials to induce relaxor ferroelectricity. The present study aims to induce a superparaelectric (SPE) state in relaxor ferroelectrics near room temperature by altering BaTiO
ferroelectric ceramics using the (Sr,Bi)TiO
-Bi(Mg
Ti
)O
system ((1-x)BT-x(SBT-BMT)). X-ray diffraction and Raman spectroscopy analysis demonstrated a shift in the crystal structure from tetragonal to cubic with an increasing x content. Notably, the compositions (except x = 0.1) satisfied the criteria for the SPE state manifestation near room temperature. The x = 0.2 specimen displayed characteristics at the boundary between the relaxor ferroelectric and SPE phases, while x ≥ 0.3 specimens exhibited increased SPE state fractions. Despite reduced maximum polarization, x ≥ 0.3 specimens showcased impressive energy storage capabilities, attributed to the enhanced SPE state, especially for x = 0.3, with impressive characteristics: a recoverable energy density (
) of ~1.12 J/cm
and efficiency (
) of ~94% at 170 kV/cm applied field. The good stability after the charge-discharge cycles reinforces the significance of the SPE phase in augmenting energy storage in relaxor ferroelectric materials, suggesting potential applications in high-energy density storage devices.