Pyroelectric And Energy Storage Properties Of Antiferroelectric And Relaxor Ceramics

Pyroelectric detectors have broad application prospects such as monitoring,temperature measurement,thermal imaging,and reconnaissance and so on due to that it can detect the ambient temperature.The core component of pyroelectric devices is pyroelectric materials,it means that the development of pyroelectric materials directly affects the development of detectors.Therefore,the research and exploration of pyroelectric materials is of great significance.Pyroelectrics refer to a class of materials that exhibit an internal polarization change in response to the variation in temperature.Macroscopically,the temperature change causes the voltage or current to appear at both ends of the material.Pyroelectric materials can be divided into crystal materials(such as LiTaO₃,LiNbO₃,K(Ta,Nb)O₃,etc.);organic polymers(such as PVDF,PVF,etc.);ferroelectric ceramic materials(such as Ba TiO₃,Pb(Mg_1/3Nb_2/3)O₃,PbTiO₃,Pb(Zr,Ti)O₃,etc.).By summarizing the research progress of pyroelectric materials in recent years,it is found that the pyroelectric coefficient(p)and figures of merit(FOMs)are maintained at a very low value.At present,most of the research on the pyroelectricity of ferroelectric materials is to reduce the ferroelectric to relaxor phase transition temperature T_F-R or Curie temperature T_c to around room temperature to obtain excellent pyroelectric performance.But when T_F-Ror T_c move to room temperature,the the residual polarization P_r is also extremely low.That is to say,the amount of charge that the material can release is limited,and the pyroelectric performance will still be difficult to greatly improve.We believe that if the thermally driven ferroelectric-antiferroelectric phase transition can be realized in antiferroelectric materials,it is possible to avoid the above-mentioned problems,thereby greatly improving the pyroelectric performance.As 5G era comes,electronic information technology is increasingly becoming integrated,networked,intelligent and miniaturized.Dielectric capacitors are playing an increasingly important application value in power electronics,communications,new energy vehicles,and pulsed power systems due to their ultra-fast charge and discharge rates and ultra-high-power density.For this reason,it is necessary to develop high-performance dielectric energy storage materials.Antiferroelectric materials are considered as the most promising to obtain higher energy storage density due to their unique external field induced antiferroelectric to ferroelectric phase transition behavior,high breakdown strength and low residual polarization.However,there are three main tricky questions in the research of high-performance dielectric energy storage materials:the first one is the lower energy storage efficiency;the second one is the lower breakdown field;the third one is the lower energy storage density.It has important significance to conduct modification on antiferroelectric materials to develop new high-performance dielectric energy storage materials.Among the well-known antiferroelectric oxides,lead-based perovskite oxide Pb_0.99Nb_0.02[(Zr_0.57Sn_0.43)_1-xTi_x]_0.98O₃(PNZST)has received extensive attention and research;On the other hand,lead-free non-stoichiometric 0.94Na_0.48Bi_0.44TiO₃-0.06Ba TiO₃(NBT-BT)can exhibit antiferroelectric characteristic due to defect effect.Based on the pyroelectric and energy storage performance,in this paper,we prapered Pb_0.99Nb_0.02[(Zr_0.57Sn_0.43)_0.937Ti_0.063]_0.98O₃:ZnO(PNZST63:ZnO),Pb_0.99Nb_0.02[(Zr_0.57Sn_0.43)_0.933Ti_0.067]_0.98O₃:ZnO(PNZST67:ZnO)and0.94Na_0.48Bi_0.44TiO₃-0.06Ba TiO₃:ZnO(NBT-BT:ZnO)composite ceramics to study the pyroelectricproperties,Pb_0.99Nb_0.02[(Zr_0.57Sn_0.43)_0.94Ti_0.06]_0.98O₃-(Na_0.5Bi_0.5)_0.94Ba_0.06TiO₃(PNZST60-(NBT-6BT))and(Pb_0.97La_0.02)(Zr_0.5Sn_0.4Ti_0.1)O₃-(Na_0.5Bi_0.5)_0.94Ba_0.06TiO₃(PLZST-(NBT-6BT))solid solution ceramics to study energy storage performance.The main contents are as follows as follows:1.It is reported that the antiferroelectric characteristic of Pb_0.99Nb_0.02[(Zr_0.57Sn_0.43)_1-xTi_x]_0.98O₃ system is extremely sensitive to the content of Ti,as the increase of Ti content,the antiferroelectric directly transitions to ferroelectric at x=0.075.This means that it is difficult to realize the thermally driven ferroelectric to antiferroelectric phase transition around the room temperature by chemical substituting.Therefore,we selected two components x=0.063 and 0.067 as the matrix material,and introduced the semiconductor ZnO into it,prapered(1-x)PNZST63:x ZnO and(1-x)PNZST67:x ZnO composite ceramics and room temperature metastable ferroelectricity was obtained.Thereby excellent pyroelectric coefficient p and figure of merit FOMs were obtained in a wide temperature range above room temperature due to thermally driven ferroelectric-antiferroelectric phase transition.These results are attributed to the internal stress and built-in electric field formed by the addition of ZnO,which caused the lattice expansion of the ceramic,further affected the ferroelectric domain switching.2.Considering the requirements of environmental protection and sustainable development for the development of lead-free devices,we selected non-stoichiometric lead-free 0.94Na_0.48Bi_0.44TiO₃-0.06Ba TiO₃(NBT-BT)with room temperature antiferroelectric characteristics,and introduced semiconductor ZnO to it to prepare(1-x)NBT-BT:x ZnO composite ceramics,and obtained room temperature ferroelectricity,the excellent pyroelectric coefficient is obtained in a wide temperature range above room temperature.3.Based on the antiferroelectric ceramics Pb_0.99Nb_0.02[(Zr_0.57Sn_0.43)_0.94Ti_0.06]_0.98O₃(PNZST60)and(Pb_0.97La_0.02)(Zr_0.5Sn_0.4Ti_0.1)O₃(PLZST),(1-x)PNZST60-x(NBT-6BT)and(1-x)PLZST-x(NBT-6BT)solid solution ceramics were prepared.The experimental results show that Ti⁴⁺entered into the lattice of PNZST60 and PLZST and partially extruded Sn⁴⁺,resulting in the separation of SnO₂ particles at the grain boundaries,thereby forming a 0-3 type composite structure.When the proportional content of NBT-6BT reaches to 0.2,the ceramics have the characteristics of ergodic relaxor,the biggiest energy storage density and energy storage efficiency is obtained at room temperature,also exhibit excellent temperature stability.