Preparation And Research Of Hexagonal Boron Nitride Based Dielectric Energy Storage Ceramics

Dielectric capacitors are energy storage devices with extremely high power density and rapid charge and discharge processes.They are widely used in electronic systems,lasers,and military industries that require high-power discharge and fast charge and discharge.However,due to the limitation of its energy storage mechanism,the existing dielectric capacitors have shortcomings such as low energy density,large volume and mass,and the existing dielectric energy storage materials cannot meet the development needs of current high-performance equipment technology.Most of the previous researches have explored the direction of polymer-based dielectric materials or ferroelectric ceramic-based dielectric materials,but polymer-based dielectrics are difficult to use in high temperature and extreme environments due to material limitations,and ferroelectric ceramic-based dielectrics also have low breakdown field strengths.Therefore,the preparation of an energy storage dielectric material that can adapt to extreme environments and have excellent dielectric properties has become the key to solving the current problem.Here we propose a new preparation method for hexagonal boron nitride-based dielectric energy storage materials.Hexagonal boron nitride is a ceramic material with high breakdown field strength,high temperature stability and chemical stability,which can perfectly adapt to various This extreme environment and high breakdown field strength make up for the disadvantage of poor breakdown resistance of ceramic-based dielectric materials.In this method,nano-diamond is doped into the hexagonal boron nitride matrix,and the volume expansion caused by the phase transformation of the diamond into graphite at high temperature not only fills the pores in the middle of the hexagonal boron nitride sheet,improves the density of the material,but also acts as a reinforcing phase.The mechanical properties of the material are improved;the resulting graphite onions act as conductive particles to induce a seepage effect in the insulating hexagonal boron nitride matrix,so that the dielectric constant of the material is improved.The final composite ceramic has excellent dielectric properties,the dielectric at 100 Hz is as high as 28100,the comprehensive mechanical properties are about 5-6times that of pure hexagonal boron nitride,and it has good moisture resistance.