High-performance asymmetric supercapacitors with lithium intercalation reaction using metal oxide-based composites as electrode materials

FeOOH-graphene nanosheets (GNS)-carbon nanotubes (CNTs) hybrid material was synthesized by the direct hydrolysis of Fe3+ on the surface of GNS-supported and CNTs-bridged frameworks. Interestingly, the as-obtained nanocomposite (FeOOH/GNS/CNTs) shows the lithium intercalation reaction characteristic in 1 M Li2SO4 aqueous solution as an electrode material for supercapacitor, providing high electrochemical performances. More importantly, benefiting from the nanosized FeOOH and highly coupled with conductive CNTs-GNS networks, which is beneficial to electron and electrolyte ion transport in the overall electrode, the as-fabricated asymmetric supercapacitor, using FeOOH/GNS/CNTs and MnO2/GNS as the negative electrode and positive electrode, respectively, exhibits superior energy density (30.4 W h kg(-1)) and good rate capability as well as excellent cycling stability (89% capacitance retention after 1000 cycles).