Enhanced energy storage performance in samarium and hafnium co-doped silver niobate ceramics

Abstract

Improving energy storage density and efficiency of antiferroelectric materials could promote their use within energy storage field, particularly in the context of pulsed power sources. In this study, Sm and Hf co-doped silver niobate (AgNbO3; AN) ceramics were prepared using traditional solid-state method. Comprehensive analysis of crystal structure, microstructure, defects, absorbance, and energy storage performance of the material was conducted. Results reveal that co-doping increased the concentration of cation vacancies and band gap, decreased the M1–M2 and M2–M3 phase transition temperatures, and enhanced the antiferroelectric phase stability and energy storage performance. The (Ag0.955Sm0.015)(Nb0.95Hf0.05)O3 ceramic exhibited energy storage density of 5.35 J/cm3 and energy storage efficiency of 73% at electric field (E) of 295 kV/cm, demonstrating significant improvement. The (Ag0.955Sm0.015)(Nb0.95Hf0.05)O3 ceramic exhibited excellent thermal stability (<5% in the range of 25 °C-125 °C) and frequency stability (<3% in the range of 1–100 Hz under E = 290 kV/cm). Additionally, the (Ag0.955Sm0.015)(Nb0.95Hf0.05)O3 ceramic exhibited ultrahigh discharge speed (∼18 μs) and high discharge energy density (4.9 J/cm3). These advantages make these ceramics promising materials for energy storage applications.