Due to the miniaturization in the electronics industry, there has been an increasing demand for reliable portable power sources. Among all the power systems, self-charging power units composed of piezoelectric materials and energy storage devices attract a lot of scientists’ attention due to their ability to convert and store human biomechanical energy. Although piezoelectric materials with good performance are used as the separator for the power units, there is not much effort to improve the electrochemical performance of the energy-storage part. Nonporous piezoelectric films without pore structure are utilized, hindering the ion diffusion process in the cell, resulting in poor cell performance. In this work, we used metal oxide nanoparticles as the sacrifice template to fabricate porous piezoelectric film for application of supercapacitor separators. Thanks to the well-designed pore structure and pore volume, the film shows a dramatic decrease in ion diffusion resistance compared to a nonporous film while retaining its good piezoelectric properties. Due to the interconnected pore structure, the performance of our separator is even comparable to a commercialized polyethylene (PE) separator. With conducting polymer as the electrode material and polyvinyl alcohol (PVA)/H₂SO₄ as the gel electrolyte, the self-charging power unit is able to go over 0.2 V by palm pressing.