Energy Storage Of PVDF-based Flexible Composites And AgNbO₃-based Ceramics

Compared with electrochemical energy storage,dielectric energy storage has fast charge and discharge capability and it can release electricity in a very short time.It can be well applied in pulse power systems and electric vehicles.Ferroelectric polymer polyvinylidene fluoride?PVDF?has the characteristics of easy processing and good toughness,so PVDF-based composites have been widely used.In this paper,we use PVDF as the matrix to uniformly disperse a certain amount of graphene oxide?GO?into the PVDF matrix,and controlling the degree of reduction of GO in PVDF-1%GO flexible composite film by controlling the composite temperature,thereby controlling the content of conductive particles in the composite film.Because it is only necessary to change the temperature and does not need to change the amount of graphene oxide,the method avoids the aggregation of rGO and effectively improved the dispersion of reduced graphene oxide?rGO?in PVDF matrix.The dielectric constant and the energy storage density are significantly improved while the dielectric loss is not increased.The quenched PVDF-1%GO flexible composite film has a large increase in the dielectric constant of the composite film because GO is reduced to rGO.In addition,the preparation process of PVDF-1%GO composite film based on temperature regulation is simple and easy,low cost,soft and it is easy to realize the chipping function of microcapacitors,and can be widely used in the field of energy storage of flexible materials.Antiferroelectric materials have broad application prospects in high-density energy storage due to their unique field-induced antiferroelectric-ferroelectric phase transition characteristics.In this paper,we study the solid solution of lead-free antiferroelectric energy storage material AgNbO₃?ANT?and relaxation ferroelectric material(Sr_0.7Bi_0.2)TiO₃?SBT?.Studies have shown that the introduction of SBT makes the field-induced ferroelectric state of the solid solution require a relatively large electric field to be induced,so the storage density of the solid solution increases with respect to ANT,and the maximum energy storage density exceeds 1J/cm³,and the corresponding energy storage efficiency also reaches about 58%.