MOF Derived Ni‐Cu Double Hydroxide Based Self‐Powered Flexible Asymmetric Supercapacitor Using Onion Scale as an Effective Bio‐Piezoelectric Separator

Abstract Modern electronic devices necessitate the utilization of compact, wearable, and flexible substrates capable of simultaneously harvesting and storing energy by merging traditional energy harvesting techniques with storage mechanisms into a singular portable device. Here, we present the fabrication of a low‐cost, sustainable, all‐solid‐state, self‐powered flexible asymmetric supercapacitor (SPASC) device. This device features MOF‐derived nickel‐copper double hydroxide nanosheets coated stainless steel (SS) fabric sheet (NCDH@SS) as the positive electrode, while manganese dioxide decorated activated porous carbon on SS fabric sheet (MnO₂‐APC@SS) acts as the negative electrode. The electrodes are isolated by a PVA‐KOH gel electrolyte, while onion scale, a bio‐piezoelectric separator, ensures effective separation. The self‐charging ability of the device is demonstrated through mechanical deformation induced by finger imparting. This rectification‐free SPASC device exhibits remarkable performance, achieving a charge up to ∼235.41 mV from the preliminary open circuit voltage of ∼20.89 mV within 180 s under ∼16.25 N of applied compressive force (charged up to ∼214.52 mV). Furthermore, three SPASC devices connected in series can power up various portable electronic devices like wristwatches, calculators, and LEDs upon frequent imparting. Our work thus demonstrates an innovative and advanced approach towards the development of sustainable, flexible, and advanced self‐powered electronics.