Piezoelectricity,Electromechanical Response And Energy Storage Behavior Of Bi_0.5Na_0.5TiO₃-based Ferroelectric Materials

Piezoelectric ceramics,as a new type of functional material that can convert electrical energy and mechanical energy,possess abvious advantages including excellent physical properties,stable chemical performance,low production cost,and easy processing into various shapes.However,the traditional lead-based piezoelectric ceramics are harmful to the environment and human beings,hence research and development of high-performance lead-free piezoelectric ceramic systems has become an inevitable trend in the future.Sodium bismuth titanate?BNT?has attracted much attention because of its high Curie temperature,good electromechanical coupling coefficient and excellent ferroelectric and piezoelectric performance.However,they also have shortcomings such as high electrical conductivity,coercive field,and difficult polarization.Therefore,in this paper,BNT materials are modified by means of solid solution modification and construction of 0-3 composite materials,and their microstructure,piezoelectric,dielectric,ferroelectric,electrostrain,and energy storage properties are systematically studiedBased on the solid solution modification method,BNT-based binary solid solution 0.93Bi_0.5Na_0.5TiO₃-0.07BaTiO₃ nanowires?BNT-BT NWs?,?1-x?Bi_0.5Na_0.5TiO₃-x(Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃?BNT-xBCZT?and BNT-based ternary solid solution?1-x?(0.94Bi_0.5Na_0.5TiO₃-0.06BaTiO₃)-xBiScO₃?BNT-BT-xBS?was successfully prepared.The introduction of BT NWs can promote the complete phase transformation from ferroelectric phase to ergodic relaxation phase at room temperature,thereby generating large strains with good temperature stability?S=0.17%?.The doping of BCZT also accelerates the phase transition from a ferroelectric phase to an ergodic relaxation phase,and produces excellent strain performance at the composition x=0.08?S=0.46%?.By introducing BS into the binary solid solution of BNT-BT,the TF-R was successfully adjusted to room temperature,thereby obtaining a large strain of 0.35%and a highly thermal stable electrostriction coefficient with 0.018 m⁴/C².By constructing BNT-based 0-3 composite materials,0.83(Bi_0.5Na_0.5)TiO₃-0.17(Bi_0.5K_0.50)TiO₃:xZnO?BNT-BKT:xZnO?and 0.92(Bi_0.5Na_0.5)TiO₃-0.06BaTiO₃-0.02(K_0.5Na_0.5)NbO₃:xBi₄Ti₃O₁₂?BNT-BT-BKT:xBiT?composite ceramic was successfully prepared.The former improves the piezoelectric properties of BNT ceramics?d33?109 pC/N?,and enhances the temperature stability of piezoelectric properties?d33 is about 73%of the initial value at 120??and the fatigue stability of strain performance?after 105 cycles,the degree of change in strain is<8%?by introducing ZnO.The latter successfully achieves large strain?S=0.2%?and electrostrictive performance with excellent temperature stability?Q33=0.0327 m4/C2?by introducing BiT.According to the solid solution modification method,?1-x??0.9CaTiO₃-0.1BiScO₃?-x(0.955Bi_0.5Na_0.5TiO₃-0.045BaAl_0.5Ta_0.5O₃)??1-x?CT-BS-xBNT-BAT?and?1-x?(0.65Bi_0.5Na_0.5TiO₃-0.35Sr_0.85Bi_0.1TiO₃)-xAgNbO₃?BNT-SBT-xAN?were successfully prepared,and their energy storage characteristics were investigated.The former successfully achieves excellent energy storage performance?Wrec=3.13 J/cm3 and ?=88.4%?owing to an increase in the breakdown field strength and a reduction in the residual polarization strength by introducing linear material CT-BS.It also obtains good frequency and fatigue stability.The latter adjusts the advantages and disadvantages of BNT-based and AN-based ceramics through SBT,and achieves excellent energy storage performance of Wrec=4.53 J/cm3 and ?=86.7%.Excellent temperature,frequency,and fatigue stability are also acquired.