Ultrahigh energy density battery-type asymmetric supercapacitors: NiMoO4 nanorod-decorated graphene and graphene/Fe2O3 quantum dots
NiMoO4, graphene, supercapacitor, energy density
ABSTRACT NiMoO4 has attracted intensive attention as one of the promising ternary metal oxides because of its high specific capacitance and electrical conductivity compared to traditional transition-metal oxides. In this study, NiMoO4 nanorods uniformly decorated on graphene nanosheets (G-NiMoO4) are synthesized through a facile hydrothermal method. The prepared G-NiMoO4 composite exhibits a high specific capacitance of 714 C·g−1 at 1 A·g−1 and an excellent rate capability, with a retention ratio of 57.7% even at 100 A·g−1. An asymmetric supercapacitor (ASC) fabricated with the G-NiMoO4 composite as the positive electrode and Fe2O3 quantum dot-decorated graphene (G-Fe2O3-QDs) as the negative electrode delivers an ultrahigh energy density of 130 Wh·kg−1, which is comparable to those of previously reported aqueous NiMoO4-based ASCs. Even when the power density reaches 33.6 kW·kg−1, an energy density of 56 Wh·kg−1 can be maintained. The ASC device exhibits outstanding cycling stability, with a capacitance retention of 113% after 40,000 cycles. These results indicate that the G-NiMoO4 composite is a promising candidate for ASCs with ultrahigh energy density and excellent cycling stability. Moreover, the present work provides an exciting guideline for the future design of high-performance supercapacitors for industrial and consumer applications via the simultaneous use of various pseudocapacitive materials with suitable potential windows as the positive and negative electrodes.
Tsinghua University Press
Jiao Yang,Wei Liu,Hao Niu,Kui Cheng,Ke Ye,Kai Zhu,Guiling Wang,Dianxue Cao,Jun Yan, Ultrahigh energy density battery-type asymmetric supercapacitors: NiMoO4 nanorod-decorated graphene and graphene/Fe2O3 quantum dots. NanoRes.2018, 11(9): 4744–4758