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

Abstract

Birnessite-type manganese dioxide (δ-MnO2) 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 MnO2. The MnO2 (535 F g−1 at 1A g−1 and 45 F g−1 at 10A g−1) and MnO2/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 MnO2/PEDOT:PSS (positive) and Fe3O4/Carbon (negative) electrodes, provided a maximum specific energy of 18 Wh kg−1 and a maximum specific power of 4.5 kW kg−1 (ΔV= 2 V, 1M Na2SO4) with 85% capacitance retention after 1000 cycles. The graphene-templated MnO2/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. Keywords: Graphene, Liquid Exfoliation, MnO2, PEDOT:PSS, Supercapacitor