新型BT-BMT-xBNT无铅高储能密度陶瓷研究

Novel BT-BMT-xBNT Lead-Free Ceramics with High Energy Storage Density

本文采用传统固相反应法,成功制备了新型无铅弛豫铁电陶瓷(1-x)[0.9BaTiO_(3)-0.1Bi(Mg_(0.25)Ta_(0.5))O_(3)]-xBi_(0.5)Na_(0.5)TiO_(3)。结果表明,较高居里温度的Bi^(0.5)Na^(0.5) TiO_(3)的引入,使得材料体系中建立了更多的以Bi—O耦合为主的极性纳米区域,弥补了因Bi(Mg_(0.25)Ta_(0.5))O_(3)的加入导致的宏观极化强度的减少,提高了材料的饱和极化强度,实现了较高储能密度的同时具有更好的温度稳定性。在245 kV/cm电场强度下,x=0.2样品的储能密度约为4.01 J/cm^(3),储能效率约为84.86%,同时该组分在20~170℃储能密度的变化率小于5%,储能效率的变化率小于6%,表现出优异的温度稳定性。

In this work,novel lead-free relaxor ferroelectric(1-x)[0.9BaTiO_(3)-0.1Bi(Mg_(0.25)Ta_(0.5))O_(3)]-xBi_(0.5)Na_(0.5)TiO_(3) ceramics were synthesized via composite strategy using the traditional solid-state process.Results indicate that the incorporation of Bi_(0.5)Na_(0.5)TiO_(3) with a high Curie temperature could not only significantly enhance the energy storage density,but also improve the temperature stability.As BNT concentration rose,the nano-scale polarization mismatch dominated by Bi—O coupling was established and enhanced,significantly compensating for the reduction of macroscopic polarization due to the addition of Bi(Mg_(0.25)Ta_(0.5))O_(3),leading to elevate saturation polarization and improve temperature stability.The ceramics which x is 0.2 show optimal energy storage features with a high energy storage density of 4.01 J/cm^(3) in the electric field of 245 kV/cm combined with a relatively high energy storage efficiency of 84.86%.Moreover,excellent temperature stabilities were noticed with the change rate of energy storage density is less than 5%and energy storage efficiency is less than 6%over a broad temperature range(20~170℃).