Design of dispersion-free dielectrics as engineering perovskite unit cells of KCa2Li(n-3)NbnO3n+1 ceramics

Abstract

Dion-Jacobson-phase perovskites have received continuous attention owing to their impressive properties such as the ability to convert them into a two-dimensional (2D) form. We report a new Dion-Jacobson phase-layered perovskite KCa2LiNb4O13 ceramics prepared by a solid-state synthesis method. The KCa2LiNb4O13 ceramic exhibited a large dielectric permittivity of 61 at 1 MHz, which is three times higher than that of KCa2Nb3O10 (epsilon r = 20), owing to an increase in the number of octahedral units (n), which causes considerably high polarization in perovskite lattices. Moreover, as engineering octahedral units by lithium ion addition instead of sodium ions, KCa2LiNb4O13 ceramic showed improved and stable dielectric properties over a wide frequency range. Moreover, the exfoliated form of 2D Ca2LiNb4O13 nanosheets was successfully synthesized via a two-step cation exchange method.