Interfacial Synthesis of δ-MnO_2 Nano-sheets with a Large Surface Area and Their Application in Electrochemical Capacitors

Birnessite-type MnO_2(δ-MnO_2) nano-sheets were successfully synthesized by an interfacial synthesis method in this work.The properties and electrochemical performance of the as-prepared δ-MnO_2 were analyzed and evaluated by scanning electron microscopy(SEM),X-ray diffraction(XRD),nitrogen adsorption measurement and electrochemical tests.This facile synthesis method enables δ-MnO_2 nanosheets to show a large specific surface area(257.5 m~2 g~(-1)).The electrochemical test results show that the specific capacitance is 272 Fg~(-1) and the specific capacitance retention is over 96.7%after 1000 cycles at a scan rate of 10 mV s~(-1).All results demonstrate that δ-MnO_2 has a great potential application in highperformance electrochemical capacitors,and this interfacial synthesis method will be a very promising method to synthesize highly active MnO_2 materials in a large scale.