Large-area α-MnO2 nanoflower arrays are synthesized by using a facile and template-free electrochemical deposition on flexible graphite paper. These nanoflower arrays exhibit a high specific capacitance of 314 F g−1 at a current density of 1 A g−1 with remarkable rate capability (61.1 % retention at 40 A g−1) and excellent cycle stability. Furthermore, the fabricated flexible symmetric supercapacitor also displays good performance and flexibility.