Energy storage and charge-discharge performance of B-site doped NBT-based lead-free ceramics

Abstract

Dielectric ceramic materials with high energy-storage density and excellent charge-discharge performance are desirable for use in dielectric capacitors. In this study, (Na 0.5 Bi 0.5 ) 0.75 Sr 0.25 TiO 3 – x Nb 2 O 5 (denoted as NBSTN x ) lead-free ceramics were prepared by a solid-state reaction method. Polarization-electric field hysteresis loops ( P–E loops) reflected the energy storage characteristics of the NBSTN x ceramics. Introducing Nb into a pure NBST ceramic can reduce the large remnant polarization ( P r ) and make the P–E loops slimmer. Through repeated trials and calculations, the maximum recoverable energy-storage density ( W rec ~ 3.25 J/cm 3 ) and energy storage efficiency ( η ~ 74.5%) were achieved for the NBSTN 0.03 ceramic at 140 kV/cm. We also tested the stability performance of the NBSTN x ceramics, where the NBSTN 0.03 ceramic exhibited the highest thermal stability (30–100 °C) and frequency stability (10–1000 Hz). The NBSTN 0.03 ceramic also had a fast discharge rate (<300 ns) and a good discharge energy-storage density ( W d ~ 1.80 J/cm 3 ). Therefore, the NBSTN 0.03 ceramic with a good energy-storage density and charge-discharge performance has excellent application prospects for practical dielectric capacitors. • A strategy incorporating B-site doping to enhance energy storage performance. • A relatively high W rec of 3.25 J/cm 3 and η of 74.5%. • Sample with 0.03 mol Nb doping shows relatively good temperature and frequency stability.