Abstract
Solid solutions of Na0.5Bi0.5TiO3(NBT)and BiNi0.5Ti0.5O3(BNiT)were prepared by a solid-state reaction route,and their electrical properties investigated by a combination of impedance spectroscopy and elec-tromotive force measurements to explore the possibility of developing mixed ionic-electronic conduc-tors based on NBT.Phase analysis showed that BNiT has a large solid solution limit in NBT(60 mol％based on X-ray diffraction),and the room temperature crystal structure changes from rhombohedral to pseudo-cubic with increasing BNiT content.Neutron diffraction revealed the coexistence of rhombohe-dral and tetragonal phases when the BNiT content ≥ 40 mol％.Electrically,incorporation of BNiT induces p-type electronic conduction into NBT by hopping of holes between Ni2+(NiNix)and Ni3+(NiNi),and there-fore changes the electrical conduction mechanism systematically from predominant oxide-ion conduction to mixed ionic-electronic conduction and then to predominant p-type electronic conduction.The total conductivity of the solid solutions showed a"V-shape"variation with increasing BNiT content.Possi-ble mechanisms for the phase evolution and the conductivity-composition relationships are discussed.Achieving high levels of ionic and electronic conductivity simultaneously in NBT by introducing elements with variable oxidation states remains challenging due to the competition between an enhanced elec-tronic component and a suppressed ionic component.Low levels of BNiT incorporation are,however,beneficial to reducing the dielectric loss of NBT for dielectric applications.
基金项目
National Natural Science Foundation of China(52072239)
National Natural Science Foundation of China(52234010)
Natural Science Foundation of Chongqing,China(cstc2021jcyjmsxmX0720)
EPSRC(EP/L027348/1)
NETL
NSTL
万方数据