[en] Highlights: • Self-powered supercapacitor with a bio-piezoelectric separator has been fabricated. • The device reveals outstanding electrochemical performance and cyclic stability. • The device can be charged either by electrically or by mechanical deformations. • Eight devices in series can instantly powers up numerous electronic appliances. Fabrication of environmental friendly, compact and wearable electronic device using a flexible substrate that synchronously harvests and stores energy by the co-ordination of a conventional energy harvesting and storage mechanism in a single portable device is highly essential to design modern electronics. Here, for the first time, we highlight the fabrication of a natural bio-piezoelectric driven self-charging asymmetric supercapacitor (SCASC) power cell consisting of nickel-cobalt double hydroxide nanoplies decorated copper oxide nanoflakes substantially grown on a flexible copper foil ([email protected] foil) as a binder free positive electrode and reduced graphene oxide coated copper foil ([email protected] foil) as negative electrode with a PVA–KOH gel electrolyte soaked perforated fish swim bladder as natural bio-piezoelectric separator (BPES). The prompt and self-charging behavior of the power cell was established by mechanically deforming it under human finger imparting and by several casual natural body motions. The rectification-free SCASC device can be charged up to 281.3 mV from its initial open circuit potential (~130.1 mV) in ~80 s under continuous human finger imparting at a frequency of 1.65 Hz. Moreover, eight serially connected SCASC devices can instantaneously light-up four red light-emitting diodes (LEDs) and power-up various portable electronic appliances on frequent imparting. Thus, the light-weight SCASC with unique design resembles its desirability for future generation smart and wearable electronics.