Triboelectric nanogenerators (TENGs) are promising innovative energy conversion devices that convert mechanical energy into electricity based on triboelectric friction. In this paper, we report the development of a single-electrode TENG (S-TENG) based on sponge-like porous polytetrafluoroethylene (PTFE) thin films. The porous PTFE thin films were fabricated via a facile approach by using deionized (DI) water as the soft template. The porosity effect on the output performance of the porous PTFE S-TENG was investigated under mechanical oscillations. The optimal porosity for achieving the maximum VOC output was found to be 5.1 V when the DI water volume fraction was 50%. The output voltage of the porous PTFE S-TENG is 1.8 times higher than that of the solid PTFE thin film based S-TENG under the same oscillation. The porous PTFE S-TENG can also generate considerable electricity by harvesting mechanical energy from human motions. An output voltage of 1.1 V was obtained when the S-TENG was pressed by a bare human hand. When pressed by a human hand within a latex glove, the output voltage reached 6.9 V, and the generated electric energy could instantaneously power 5 commercial green light emitting diodes (LEDs) without any energy storage process. This development of the porous PTFE S-TENG could open a new avenue towards developing self-powered personal electronics, owing to its flexibility, simple one-electrode structure, and ability to harvest mechanical energy from human motions.