High Pseudocapacitive Performance of MnO2 Nanowires on Recyclable Electrodes

Manganese oxides are promising pseudocapacitve materials for achieving both high power and energy densities in pseudocapacitors. However, it remains a great challenge to develop MnO2 -based high-performance electrodes due to their low electrical conductance and poor stability. Here we show that MnO2 nanowires anchored on electrochemically modified graphite foil (EMGF) have a high areal capacitance of 167 mF cm(-2) at a discharge current density of 0.2 mA cm(-2) and a high capacitance retention after 5000 charge/discharge cycles (115 %), which are among the best values reported for any MnO2 -based hybrid structures. The EMGF support can also be recycled and the newly deposited MnO2 -based hybrids retain similarly high performance. These results demonstrate the successful preparation of pseudocapacitors with high capacity and cycling stability, which may open a new opportunity towards a sustainable and environmentally friendly method of utilizing electrochemical energy storage devices.