Polymeric　dielectrics　have　wide　range　of　applications　in　the　field　of　electrical　energy　storage　because　of　their　light　weight　and　easy　processing.　However,　the　state-of-the-art　polymer　dielectrics,　such　as　biaxially　orientated　polypropylene,　could　not　meet　the　demand　of　minimization　of　electronic　devices　because　of　its　low　energy　density.　Recently,　poly(vinylidene　fluoride)　(PVDF)　based　ferroelectric　polymers　have　attracted　considerable　interests　for　energy　storage　applications　because　of　their　high　permittivity　and　high　breakdown　strength.　Unfortunately,　the　high　dielectric　loss　and/or　high　remnant　polarization　of　PVDF-based　polymers　seriously　limits　their　practical　applications　for　electrical　energy　storage.　Since　the　discovery　of　relaxor　ferroelectric　behavior　was　firstly　reported　in　irradiated　poly(vinylidene　fluoride-trifluoroethylene)　(P(VDF-TrFE))　copolymer,　many　strategies　have　been　developed　to　enhanced　the　electrical　energy　storage　capability,　including　copolymerization,　grafting,　blending　and　fabricating　of　multilayer.　How　these　methods　affect　the　polymorphs,　crystallinity,　crystal　size　of　PVDF-based　polymers　and　the　connection　between　these　microstructures　and　their　corresponding　energy　storage　properties　are　discussed　in　detail.　(C)　2017　Chinese　Chemical　Society　and　Institute　of　Materia　Medica,　Chinese　Academy　of　Medical　Sciences.　Published　by　Elsevier　B.V.　All　rights　reserved.