Effect of temperature on the pseudo-capacitive behavior of freestanding MnO2@carbon nanofibers composites electrodes in mild electrolyte

► Hierarchical δ-MnO2 nanoflakes @carbon nanofibers composites are prepared. ► Effect of temperature on pseudo-capacitive behaviors is extensively studied. ► The composites show good electrochemical performance in range of 0-75 °C ► The δ-MnO2 is found to evolve to γ-MnO2 nanorods during cycling test at 75 °C.