Examples of the present invention relate generally to high electric energy density polymer film capacitors with high charge-discharge efficiency and fast discharge speed. For example, a high energy density polymer capacitor may be fabricated using a polymer blend comprising one or more high dielectric constant PVDF-based polymers (including homopolymers, copolymers and/or terpolymers) and one or more other polymer with low dielectric loss and high volume resistivity compared to the one or more PVDF-based polymers. An example film capacitor may comprise a high temperature fluoropolymer with dielectric loss lower than 0.2% and good film manufacturability. Polymer films can be stretched and orientated at least in one direction to make thinner films with improved performance. Film capacitors can be made by winding metallized films, plain films with metal foils, or using a hybrid construction where the dielectric films comprise the new compositions. Capacitors can also have a multilayer construction where the films are metallized.