La/Mn Codoped AgNbO₃ Lead-Free Antiferroelectric Ceramics with Large Energy Density and Power Density

Abstract

Dielectric materials with high energy density have attracted much attention due to their potential applications in modern electronics and electrical power systems. In this work, a large energy storage density of 3.2 J/cm3 was achieved in La/Mn codoped AgNbO3 antiferroelectric ceramics through enhancing the ferroelectric-antiferroelectric backward transition field and reducing the remnant polarization simultaneously. Moreover, the coexistence of Mn2+/Mn3+ at A-site disrupts the randomly disordered Nb5+ at high temperature, leading to the disappearance of freezing temperature Tf. This results in a stable antiferroelectric phase M2 over a broad temperature and thus a good temperature stability of energy density was achieved. Furthermore, the pulse discharge performance of AgNbO3-based ceramics was evaluated for the first time and a maximum power density of 390 MW/cm3 was obtained in Mn-doped Ag0.97La0.01NbO3 ceramics, which is about 8 times larger than the previously reported maximum value (50 MW/cm3). These results reveal Mn-doped Ag0.97La0.01NbO3 ceramics as a good candidate for lead-free high power capacitors.