Abstract: Triboelectric nanogenerators (TENGs) are promising innovative energy conversion devices that convert mechanical energy to electricity based on triboelectric friction. We developed a series of TENGs based on sponge-like porous polymer thin films such as polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE). The porosity effect on the output performance of the porous TENG was investigated under mechanical impacts. The output voltage of the porous TENG is obvious higher than that of the solid polymer thin film based TENG under the same condition. The porous TENG can also generate considerable electricity by harvesting mechanical energy from human motions. The generated electric energy could instantaneously power some light emitting diodes (LEDs) and other small electronics without any energy storage process. The development of the porous TENGs could open a new avenue toward developing self-powered personal electronics, owing to their flexibility, simple structure, and the ability to harvest mechanical energy from human motions.