Synthesis and characterization of polypyrrole/nickel hydroxide/sulfonated graphene oxide ternary composite for all-solid-state asymmetric supercapacitor

The polypyrrole/nickel hydroxide/sulfonated graphene oxide (PPy/Ni(OH)2/SGO) ternary composite is prepared as supercapacitor electrode material by stepwise loading of Ni(OH)2 and PPy into SGO through hydrothermal and chemical oxidative polymerization process. The PPy and Ni(OH)2 are incorporated into composite to act as pseudocapacitive electrode with low cost and high capacitance. The SGO obtained by the surface modification of graphene has a higher hydrophilic property and larger specific surface to provide charge transfer path. The creative PPy/Ni(OH)2/SGO (P-N-S) ternary composite shows a high specific capacitance of 1632.5 F g−1 at a current density of 1 A g−1 in 6 M KOH solution. A capacitance retention of 86% after 1000 cycles proves that the P-N-S has a good cycling stability. The all-solid-state asymmetric supercapacitor (ASC) is assembled with P-N-S cathode material and activated carbon (AC) as anode material to exhibit a high special capacitance of 224 F g−1 at 1 A g−1, a large energy density (79.6 Wh Kg−1) and power density (0.8 kW kg−1), and a stable cycle life (the capacitance retention rate of 60% after 5000 cycles at 10 A g−1). Two ASCs in series can lighten up a green LED indicator.