Relaxor dielectric ceramic capacitors are very attractive for high-power energy storage.However,the low breakdown strength severely restricts improvements to the energy storage density and practical application.Here,a...Relaxor dielectric ceramic capacitors are very attractive for high-power energy storage.However,the low breakdown strength severely restricts improvements to the energy storage density and practical application.Here,a strategy of designing small grain sizes and abundant amorphous grain boundaries is proposed to improve the energy storage properties under the guidance of phase field theory.0.925(K_(0.5)Na_(0.5))NbO_(3)-e0.075Bi(Zn_(2/3)(Ta_(0.5)Nb_(0.5))1/3)O_(3)(KNNe-BZTN)relaxor ferroelectric ceramic is taken as an example to verify our strategy.The grain sizes and grain boundaries of the KNNeBZTN ceramics are carefully controlled by the high-energy ball milling method and twoestep sintering strategy.Impedance analysis and diffusion reflectance spectra demonstrate that KNNeBZTN ceramics with a small grain size and abundant amorphous grain boundary exhibit a lower charge carrier concentration and higher band gap.As a consequence,the breakdown electric field of KNNeBZTN ceramics increases from 222 kV/cm to 317 kV/cm when the grain size is decreased from 410 nm to 200 nm,accompanied by a slightly degraded maximum polarization.KNNeBZTN ceramics with an average grain size of~250 nm and abundant amorphous grain boundaries exhibit optimum energy storage properties with a high recoverable energy density of 4.02 J/cm^(3) and a high energy efficiency of 87.4%.This successful local structural design opens up a new paradigm to improve the energy storage performance of other dielectric ceramic capacitors for electrical energy storage.展开更多
Sensors are widely used to acquire biological and environmental information for medical diagnosis,and health and environmental monitoring.Graphene is a promising new sensor material that has been widely used in sensor...Sensors are widely used to acquire biological and environmental information for medical diagnosis,and health and environmental monitoring.Graphene is a promising new sensor material that has been widely used in sensor fabrication in recent years.Compared with many other existing graphene preparation methods,laser-scribed graphene(LSG)is simple,low-cost,environmentally friendly,and has good conductivity and high thermal stability,making it widely used in the sensor field.This paper summarizes existing LSG methods for sensor fabrication.Primary LSG preparation methods and their variants are introduced first,followed by a summary of LSG modification methods designed explicitly for sensor fabrication.Subsequently,the applications of LSG in stress,bio,gas,temperature,and humidity sensors are summarized with a particular focus on multifunctional integrated sensors.Finally,the current challenges and prospects of LSG-based sensors are discussed.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52072150,51702119,51702122,51972146)Young Elite Scientists Sponsorship Program by CAST.
文摘Relaxor dielectric ceramic capacitors are very attractive for high-power energy storage.However,the low breakdown strength severely restricts improvements to the energy storage density and practical application.Here,a strategy of designing small grain sizes and abundant amorphous grain boundaries is proposed to improve the energy storage properties under the guidance of phase field theory.0.925(K_(0.5)Na_(0.5))NbO_(3)-e0.075Bi(Zn_(2/3)(Ta_(0.5)Nb_(0.5))1/3)O_(3)(KNNe-BZTN)relaxor ferroelectric ceramic is taken as an example to verify our strategy.The grain sizes and grain boundaries of the KNNeBZTN ceramics are carefully controlled by the high-energy ball milling method and twoestep sintering strategy.Impedance analysis and diffusion reflectance spectra demonstrate that KNNeBZTN ceramics with a small grain size and abundant amorphous grain boundary exhibit a lower charge carrier concentration and higher band gap.As a consequence,the breakdown electric field of KNNeBZTN ceramics increases from 222 kV/cm to 317 kV/cm when the grain size is decreased from 410 nm to 200 nm,accompanied by a slightly degraded maximum polarization.KNNeBZTN ceramics with an average grain size of~250 nm and abundant amorphous grain boundaries exhibit optimum energy storage properties with a high recoverable energy density of 4.02 J/cm^(3) and a high energy efficiency of 87.4%.This successful local structural design opens up a new paradigm to improve the energy storage performance of other dielectric ceramic capacitors for electrical energy storage.
基金the Science and Technology Commission of Shanghai Municipality(Grant No.21DZ1100500)Shanghai Municipal Science and Technology Major Project,and Shanghai Frontiers Science Center Program(2021-2025 No.20)+2 种基金Fangyi Zhang acknowledges the continued support from the Queensland University of Technology(QUT)through the Centre for Robotics.Zhengfen Wan thanks the National Natural Science Foundation of China(Grant No.62105206)the China Postdoctoral Science Foundation(No.2021M692137)for their supportXi Chen acknowledges the support from the National Natural Science Foundation of China(Grant No.11974247).
文摘Sensors are widely used to acquire biological and environmental information for medical diagnosis,and health and environmental monitoring.Graphene is a promising new sensor material that has been widely used in sensor fabrication in recent years.Compared with many other existing graphene preparation methods,laser-scribed graphene(LSG)is simple,low-cost,environmentally friendly,and has good conductivity and high thermal stability,making it widely used in the sensor field.This paper summarizes existing LSG methods for sensor fabrication.Primary LSG preparation methods and their variants are introduced first,followed by a summary of LSG modification methods designed explicitly for sensor fabrication.Subsequently,the applications of LSG in stress,bio,gas,temperature,and humidity sensors are summarized with a particular focus on multifunctional integrated sensors.Finally,the current challenges and prospects of LSG-based sensors are discussed.
