PEDOT:PSS Enhanced Electrochemical Capacitive Performance of Graphene-Templated δ-MnO2

Abstract

Birnessite-type manganese dioxide (-MnO 2 ) with hierarchical micro-/mesoporosity was synthesized via sacrificial graphene template approach under mild hydrothermal conditions for the first time. Graphene template was obtained by a surfactant (cetyltrimethylammonium bromide, CTAB) assisted liquid phase exfoliation (LPE) in water. A thin PEDOT:PSS (poly (3,4-ethylene dioxythiophene): poly (styrene sulfonate)) layer was applied to improve electrical conductivity and rate capability of MnO 2 . The MnO 2 (535 F g -1 at 1 A g -1 and 45 F g -1 at 10 A g -1 ) and MnO 2 /PEDOT:PSS nanocomposite (550 F g -1 at 1 A g -1 and 141 F g -1 at 10 A g -1 ) delivered electrochemical performances superior to their previously reported counterparts. An asymmetric supercapacitor, composed of MnO 2 /PEDOT:PSS (positive) and Fe 3 O 4 /Carbon (negative) electrodes, provided a maximum specific energy of 18 Wh kg -1 and a maximum specific power of 4.5 kW kg -1 (V= 2 V, 1M Na 2 SO 4 ) with 85% capacitance retention after 1000 cycles. The graphene-templated MnO 2 /PEDOT:PSS nanocomposite obtained by a simple and green approach promises for future energy storage applications with its remarkable capacitance, rate performance and cycling stability.