MnO2 nanograsses on porous carbon cloth for flexible solid-state asymmetric supercapacitors with high energy density

Flexible solid-state supercapacitors (SCs) have shown great potential in portable electronics. However, the development of MnO2-based electrodes for flexible SCs is hampered by the low energy density, especially on the whole electrode basis, as a result of the small mass loading and poor utilization of MnO2. Here high mass loading of 4.5 mg/cm(2) and large capacitance of 464 F/g ( 2088 mF/cm(2)) for MnO2 nanograsses were achieved by taking use of porous carbon cloth (TCC) which has large specific surface area. Benefiting from the full utilization of MnO2, high energy density of 841 mu Wh/cm(2) and robust cyclic stability (96% capacitance retention after 20000 cycles) are achieved by assembling an efficient asymmetric supercapacitor (ASC) with 2 V operating voltage. These results open up new paths for developing high-performance electrode materials and applying for advanced energy storage devices.