As a high-dielectric separator, a wide variety of polymers like poly(vinylidene fluoride) (PVDF) and its co-polymer such as poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) are commonly employed due to having modifiable electrical properties with impregnating suitable dopants in the fabrication of a high-performance charge storage device. In this report, improvement of efficiency has been studied by tuning the doping concentration of triturated material like ultra-low-density copper sulphate (ULDCS) within PVDF-HFP matrix and found a massive increment in β phase (β%), dielectric constant (er) and ac conductivity (σac) with ∼ 2.3, ∼ 56 and ∼ 21 fold (at 100-Hz frequency), respectively, at a critical percentage of 10-ml doping compared to the pristine polymer matrix. One crucial factor like dielectric leakage has been taken into account intensely with reduction of ∼ 2.6 times at 100-Hz frequency with respect to the pristine one to obtain excellent behaviour of the separator. These extremely desirable properties can make the sample a very promising candidate to be used as a high-dielectric separator of an extraordinary charge storage device. In this context, a super-charge storage device has been fabricated using our synthesized high-dielectric material as a separator, and the device performance is amplified to a greater extent. Generation of high potential up to 3.77 V with high rate of retentivity (∼ 88.86%) is the key function of our device, and the efficiency of the device has also been verified by lighting up to 25 light-emitting diodes (LEDs) for 10 min.