Bi0.5Na0.5TiO3-based energy storage ceramics with excellent comprehensive performance by constructing dynamic nanoscale domains and high intrinsic breakdown strength
Changbai Long, Ziqian Su, Anwei Xu, Heng Huang, Laijun Liu, Long Gu, Wei Ren, Haijun Wu, Xiangdong Ding
Abstract
Lead-free ceramic-based dielectric capacitors show huge potential in electrical energy storage in pulsed power systems due to their fast charge/discharge rate, ultrahigh power density and environmental friendliness. However, unsatisfied charge/discharge performance characterized by inferior recoverable energy storage density ( W rec generally <5 J/cm 3 ) has become a key bottleneck to restrict their applications in cutting-edge energy storage devices. In this paper, we focus on simultaneously realizing ultrahigh W rec and efficiency ( ƞ ) in eco-friendly Bi 0.5 Na 0.5 TiO 3 (BNT)-based dielectric ceramics via chemical doping. Interestingly, highly dynamic polar nanoregions (PNRs) and nanodomains are constructed by incorporating Sr 0.7 Nd 0.2 TiO 3 (SNT) into 0.94BNT-0.06BaTiO 3 . Of great importance, the resulting relaxor ferroelectrics (RFEs) exhibit high bulk resistivity, submicron grain size and wide band gap due to high level of SNT doping accompanying with 1 at% Nb donor doping. Therefore, excellent energy storage properties with ultrahigh W rec ∼8.08 J/cm 3 and ƞ ∼92.1% are achieved due to coexistence of large polarization difference (Δ P = P max − P r ) and giant dielectric breakdown electric field ( E b ∼540 kV/cm). Furthermore, excellent temperature / frequency/cycling stability characterized by Δ W rec < ±4% and Δ η < ±2% ensure the energy storage applications of the studied dielectric ceramics over an enormous range of scales.