Enhanced energy storage performance under low electric field in Sm3+ doped AgNbO3 ceramics

TLDR

The study examined how Sm³⁺ doping affects the structure, properties, and energy storage performance of AgNbO₃ ceramics. Ag₁₋₃ₓSmₓNbO₃ (0 ≤ x ≤ 0.025) antiferroelectric ceramics were synthesized via solid‑state processing. Sm³⁺ doping reduced grain size, expanded the high‑temperature antiferroelectric phase, suppressed ferroelectricity, and yielded a 1.5‑fold increase in recoverable energy density (3.8 J cm⁻³, 73 % efficiency) with ±5 % stability from 25 °C to 125 °C, making Ag₀.₉₇Sm₀.₀₁NbO₃ a promising lead‑free energy‑storage material.

Abstract

Herein, Ag1-3xSmxNbO3 (0 ≤ x ≤ 0.025) antiferroelectric ceramics were successfully synthesized by solid state methods. The effect of Sm3+ doping on the structure, property and energy storage performance were studied. With the increasing Sm3+ concentrations, the average grain size decreased. Meanwhile, the stability of high temperature M phases (i.e., the structure between Tf and T3) was expanded, which led to low loss for energy storage. Both of structure analysis and ferroelectric tests revealed the existence of weakly polar/AFE-like phase below Tf. The Sm3+ doping tended to suppress the ferroelectric behavior and expand the stability of antiferroelectricity. Consequently, a significantly enhanced energy storage performance (Wrec = 3.8 J/cm3, η = 73 %) could be achieved in Ag0.97Sm0.01NbO3 ceramic, which was almost 1.5 times larger than that in non-doped AgNbO3 (Wrec = 2.4 J/cm3, η = 45 %) under the similar applied field of 1705 kV/cm±. In particular, the performance of the ceramic showed great temperature stability with variation of ±5 % from 25 °C to 125 °C. These results indicated that the Ag0.97Sm0.01NbO3 ceramic could be an ideal lead-free candidate used in the energy storage field.