High-energy density dielectrics for electrostatic capacitors are in urgent demand for advanced electronics and electrical power systems.Poly(vinylidene fluoride)(PVDF)based nanocomposites have attracted remarkable att...High-energy density dielectrics for electrostatic capacitors are in urgent demand for advanced electronics and electrical power systems.Poly(vinylidene fluoride)(PVDF)based nanocomposites have attracted remarkable attention by intrinsic high polarization,flexibility,low density,and outstanding processability.However,it is still challenging to achieve significant improvement in energy density due to the common contradictions between electric polarization and breakdown strength.Here,we proposed a novel facile strategy that simultaneously achieves the construction of in-plane oriented BaTiO3 nanowires and crystallization modulation of PVDF matrix via an in-situ uniaxial stretch process.The polar phase transition and enhanced Young's modulus facilitate the synergetic improvement of electric polarization and voltage endurance capability for PVDF matrix.Additionally,the aligned distribution of nanowires could reduce the contact probability of nanowire tips,thus alleviating electric field concentration and hindering the conductive path.Finally,a record high energy density of 38.3 J/cm3 and 40.9 J/cm3 are achieved for single layer and optimized sandwich-structured nanocomposite,respectively.This work provides a unique structural design and universal method for dielectric nanocomposites with ultrahigh energy density,which presents a promising prospect of practical application for modern energy storage systems.展开更多
3D printing of flexible piezoelectric composites(3D-FPCs)is increasingly attracting the attention due to its unique advantage for customized smart applications.However,current research mainly focuses on the 0-3 piezoe...3D printing of flexible piezoelectric composites(3D-FPCs)is increasingly attracting the attention due to its unique advantage for customized smart applications.However,current research mainly focuses on the 0-3 piezoelectric composites,in which the piezoelectric ceramics are embedded in polymer matrix in the form of particles.The poor connectivity between particles much reduces the conduction of strain and charge in the composites,seriously limiting its application in actuation.In this work,a continuous lead zirconate titanate(PZT)double-layer ceramic scaffold was prepared by 3D printing and assembled with epoxy resin and interdigital electrodes together to manufacture a multifunctional device.The 3D-FPCs exhibit a free strain of 1830 ppm in actuating and are able to actuate a stainless-steel cantilever beam to produce a tip displacement of 5.71 mm.Additionally,the devices exhibit a sensitivity of 26.81V/g in sensing applications.Furthermore,3D-FPCs are demonstrated as actuators for mobile small robots and wearable sensors for sensing joint activities.展开更多
基金the support by National Natural Science Foundation of China(52172265 and 52002404)Excellent Youth Science Foundation of Hunan Province(2022JJ20067)+1 种基金Central South University Innovation-Driven Research Program(2023CXQD010)the State Key Laboratory of Powder Metallurgy,Central South University,Changsha,China.
文摘High-energy density dielectrics for electrostatic capacitors are in urgent demand for advanced electronics and electrical power systems.Poly(vinylidene fluoride)(PVDF)based nanocomposites have attracted remarkable attention by intrinsic high polarization,flexibility,low density,and outstanding processability.However,it is still challenging to achieve significant improvement in energy density due to the common contradictions between electric polarization and breakdown strength.Here,we proposed a novel facile strategy that simultaneously achieves the construction of in-plane oriented BaTiO3 nanowires and crystallization modulation of PVDF matrix via an in-situ uniaxial stretch process.The polar phase transition and enhanced Young's modulus facilitate the synergetic improvement of electric polarization and voltage endurance capability for PVDF matrix.Additionally,the aligned distribution of nanowires could reduce the contact probability of nanowire tips,thus alleviating electric field concentration and hindering the conductive path.Finally,a record high energy density of 38.3 J/cm3 and 40.9 J/cm3 are achieved for single layer and optimized sandwich-structured nanocomposite,respectively.This work provides a unique structural design and universal method for dielectric nanocomposites with ultrahigh energy density,which presents a promising prospect of practical application for modern energy storage systems.
基金supported by the National Key R&D Program of China(2020YFA0711700)the National Natural Science Foundation of China(Grant No.U19A2087,52172134,52102150)the Science and Technology Innovation Program of Hunan Province(No.2022RC1029).
文摘3D printing of flexible piezoelectric composites(3D-FPCs)is increasingly attracting the attention due to its unique advantage for customized smart applications.However,current research mainly focuses on the 0-3 piezoelectric composites,in which the piezoelectric ceramics are embedded in polymer matrix in the form of particles.The poor connectivity between particles much reduces the conduction of strain and charge in the composites,seriously limiting its application in actuation.In this work,a continuous lead zirconate titanate(PZT)double-layer ceramic scaffold was prepared by 3D printing and assembled with epoxy resin and interdigital electrodes together to manufacture a multifunctional device.The 3D-FPCs exhibit a free strain of 1830 ppm in actuating and are able to actuate a stainless-steel cantilever beam to produce a tip displacement of 5.71 mm.Additionally,the devices exhibit a sensitivity of 26.81V/g in sensing applications.Furthermore,3D-FPCs are demonstrated as actuators for mobile small robots and wearable sensors for sensing joint activities.
