The present work demonstrates the very first approach to enhancing the output voltage of a thermoelectric generator by introducing highly charged polyimide‐based dielectrics. High charge density over 320 µC m−2 in C60‐containing block polyimide (PI‐b‐C60) having excellent charge retention characteristics is obtained through an ion injection process, attached at the cooling part of a thermoelectric generator consisting of Cu/p‐type BiSbTe/Au/Cr/SiO2/Si. This significantly increases the electric potential difference across the thermoelectric generator (TEG) from 4.2 to 8.2 mV at the temperature difference of 20 K, and this increase can be maintained over 1 day. Density functional theory studies support that the enhancement depends on the dielectric constant and the insulating properties of the dielectric. Finally, a TEG consisting of 81 p‐type BiSbTe legs with PI‐b‐C60 generates an output voltage of 0.632 V, and the charged energy of the 10 mF‐capacitor is boosted by 30 s. These results demonstrate the possibility of large‐area TEG fabrication without the need for modification of the TE materials by introducing a new mechanism which is based on the coupling effect between thermoelectric carriers and triboelectric charges.