%0 Journal Article %A Sankar, Kalimuthu Vijaya %A Seo, Youngho %A Lee, Su Chan %A Jun, Seong Chan %D 2018 %T Redox Additive-Improved Electrochemically and Structurally Robust Binder-Free Nickel Pyrophosphate Nanorods as Superior Cathode for Hybrid Supercapacitors %U https://acs.figshare.com/articles/journal_contribution/Redox_Additive-Improved_Electrochemically_and_Structurally_Robust_Binder-Free_Nickel_Pyrophosphate_Nanorods_as_Superior_Cathode_for_Hybrid_Supercapacitors/5926276 %R 10.1021/acsami.7b19357.s001 %2 https://acs.figshare.com/ndownloader/files/10592707 %K N-doped %K electrolyte %K battery-type nickel pyrophosphate %K battery-type redox additive %K nickel pyrophosphate 1 D nanorods %K charge storage capacity %K graphene oxide %K supercapacitor %K cm %K capacitance %K life %K power density %K Redox Additive-Improved Electrochemically %K anode %K performance %K material %K Structurally Robust Binder-Free Nickel Pyrophosphate Nanorods %K kg %K 75 mg K 3 %K 1 M KOH %X For several decades, one of the great challenges for constructing a high-energy supercapacitor has been designing electrode materials with high performance. Herein, we report for the first time to our knowledge a novel hybrid supercapacitor composed of battery-type nickel pyrophosphate one-dimensional (1D) nanorods and capacitive-type N-doped reduced graphene oxide as the cathode and anode, respectively, in an aqueous redox-added electrolyte. More importantly, ex situ microscopic images of the nickel pyrophosphate 1D nanorods revealed that the presence of the battery-type redox additive enhanced the charge storage capacity and cycling life as a result of the microstructure stability. The nickel pyrophosphate 1D nanorods exhibited their maximum specific capacitance (8120 mF cm–2 at 5 mV s–1) and energy density (0.22 mWh cm–2 at a power density of 1.375 mW cm–2) in 1 M KOH + 75 mg K3[Fe­(CN)6] electrolyte. On the other side, the N-doped reduced graphene oxide delivered an excellent electrochemical performance, demonstrating that it was an appropriate anode. A hybrid supercapacitor showed a high specific capacitance (224 F g–1 at a current density of 1 A g–1) and high energy density (70 Wh kg–1 at a power density of 750 W kg–1), as well as a long cycle life (a Coulombic efficiency of 96% over 5000 cycles), which was a higher performance than most of those in recent reports. Our results suggested that the materials and redox additive in this novel design hold great promise for potential applications in a next-generation hybrid supercapacitor. %I ACS Publications