Many industry applications require electronic circuits and systems to operate at high temperatures over 150 °C. Although planar microsupercapacitors (MSCs) have great potential for miniaturized on-chip integrated energy storage components, most of the present devices can only operate at low temperatures (<100 °C). In this work, we have demonstrated a facile process to fabricate activated graphene-based MSCs that can work at temperatures as high as 150 °C with high areal capacitance over 10 mF cm−2and good cycling performance. Remarkably, the devices exhibit no capacitance degradation during temperature cycling between 25 °C and 150 °C, thanks to the thermal stability of the active components.