A carbon modified MnO2 nanosheet array as a stable high-capacitance supercapacitor electrode

A carbon-modified manganese dioxide (MnO2@C) nanosheet array has been synthesized on a titanium foil current collector via a facile hydrothermal method followed by carbonization of glucose pre-adsorbed onto the nanosheets. The direct growth of MnO2@C nanosheets on a current collector leads to enhanced electron transport/collection and more sufficient ion adsorption-desorption. Carbon modification proves to enhance the electrical conductivity of MnO2. With the elegant combination of ordered array electrode architecture with conductive carbon, our MnO2@C nanosheet array displays well-defined capacitive features with both high gravimetric and areal capacitances (similar to 622 F g(-1) and 143 mF cm(-2); much higher than those of our pristine MnO2 film and other reported MnO2 electrodes), good rate capability and outstanding cycling stability up to 4000 times (only 5.9% loss). The present study provides an alternative way to design a high-performance MnO2-based supercapacitor electrode and the concept is extendable to other pseudocapacitive electrodes.