This research presents a novel investigation into the intricate relationship between temperature and the performance of polymeric triboelectric nanogenerators experimentally and theoretically. A comprehensive investigation has been conducted to delve into the underlying mechanisms governing the temperature dependence of a triboelectric nanogenerator. The study centers on a meticulously fabricated triboelectric nanogenerator using a polyimide (PI) nanofiber membrane and encompasses a broad temperature spectrum, analyzing behavior at both room temperature and elevated temperatures. The developed PI nanofiber membrane functions as a versatile platform for converting mechanical energy into electrical with potential to harvest energy even from ultra-low frequency movements like the human pulse or the act of scratching. Additionally, the material boasts a sophisticated triboelectric response strategy. This means it exhibits its peak performance within a specific temperature range, optimizing energy conversion efficiency under these conditions. Open circuit voltage (VOC) reaches 11.76 V at 160 °C, an 84.4 % improvement compared to room temperature. A Kelvin probe force microscopy (KPFM) and fast Fourier transform (FFT) analyses have been performed for the first time to decouple the energy conversion mechanism, confirming its primary dependence on triboelectricity. A comprehensive theoretical study explores the working mechanisms of contact electrification (CE) and the triboelectric effect (TE) during temperature elevation in these nanogenerators (TENGs). This work highlights the potential of PI nanofibers as high-performance, flexible nanogenerators, particularly for applications requiring operation in smart, high-temperature environments. The emphasis on decoupling the mechanism through novel techniques and a theoretical framework on the temperature dependence strengthens the originality and contribution of the study.