Influence of Mn Ions' Insertion in Pseudo-Tetragonal Phased CaBi 4 Ti 4 O 15 -Based Ceramics for Highly Efficient Energy Storage Devices and High-Temperature Piezoelectric Applications.

In the present era of advanced technology, the surge for suitable multifunctional materials capable of operating above 300 °C has increased for the utilization of high-temperature piezoelectric devices. For this purpose, a pseudo-tetragonal phased CaBi 4 Ti 3.98 (Nb 0.5 Fe 0.5 ) 0.02 O 15 : x wt%MnO 2 (CBTNF: x Mn), with x = 0-0.20, ceramic system has been engineered for the investigation of structural, ferroelectric, dielectric and high-temperature-dependent piezoelectric properties. XRD analysis confirms that low-content Mn-ion insertion at the lattice sites of CBTNF does not distort the pseudo-tetragonal phase lattice of CBTNF: x Mn ceramics, but enhances the functional behavior of the ceramic system, specifically at x = 0.15 wt%Mn. Compared to pure CBT and CBTNF ceramics, CBTNF:0.15Mn has demonstrated a highly dense relative density (~96%), a saturated polarization ( P S ) of 15.89 µC/cm 2 , a storage energy density ( W ST ) of ~1.82 J/cm 3 , an energy-conversion efficiency ( ƞ ) of ~51% and an upgraded piezoelectric behavior ( d 33 ) of 27.1 pC/N at room temperature. Sharp temperature-dependent dielectric constant ( ε r ) peaks display the solid ferroelectric behavior of the CBTNF:0.15Mn sample with a Curie temperature ( T C ) of 766 °C. The thermally stable piezoelectric performance of the CBTNF:0.15Mn ceramic was observed at 600 °C, with just a 0.8% d 33 loss (25 pC/N). The achieved results signify that multi-valence Mn ions have effectively intercalated at the lattice sites of the pseudo-tetragonal phased CBTNF counterpart and enhanced the multifunctional properties of the ceramic system, proving it to be a durable contender for utilization in energy-storage applications and stable high-temperature piezoelectric applications.