Ni(OH)₂ Nanosheets Grown on Reduced Graphene Oxide for Supercapacitor Electrodes

Abstract

Ni­(OH)2 has low production cost and high theoretical specific capacity, while on account of the poor electronic conductivity, it shows inferior electrochemical performance including cycling stability and rate capability. This work focuses on a composite material that is in situ grown Ni­(OH)2 nanosheets on reduced graphene oxide (rGO), and employing the fewer-defect rGO to build a three-dimensional conductive network provides outstanding conductivity. The specific capacitances (C m) of the Ni­(OH)2/rGO (NHG) electrode are 2776 F·g–1 at 2 A·g–1 and even 1570 F·g–1 at 50 A·g–1, demonstrating remarkable rate capability. It indicates that the combination of the nano grown Ni­(OH)2 and rGO conductive substrate shortens the ion diffusion path and increases the electron transfer rate; hence, the composite rate capability has been significantly improved. The composite materials and active carbon were combined to be an asymmetric supercapacitor, which had a high energy density of 39.24 Wh·kg–1 at 1962 W·kg–1. After 10,000 cycles at 5 A·g–1, the capacity retains 91.4%.

Facile Fabrication of Iron Cobalt Sulfide Nanoparticles within N-Doped Graphene for High-Performance Supercapacitors

“…The assembled ASC device achieves an extraordinary energy density of 79.3 Wh kg –1 at a power density of 804 W kg –1 . Even at a high power density of 15,069 W kg –1 , the energy density of the ASC device still keeps 47.3 W h kg –1 , which is predominant in comparison with the previously reported ASCs, such as CCSe-HSs//AC (53.86 W h kg –1 at 800 W kg –1 ), (NiOH) 2 /rGO//AC (39.64 W h kg –1 at 1962 W kg –1 ), NiZn-LDH@NiCoSe 2 //AC (49 W h kg –1 at 160 W kg –1 ), NiO/CeO 2 //Bi-Ni-O (78 W h kg –1 at 201 W kg –1 ), CNTs/K x MnO 2 //Ti 3 C 2 T x /MoO 3 (36.4 W h kg –1 at 863 W kg –1 ), and NiCoFe-LDH/Ti 3 C 2 //rGO (54.4 W h kg –1 at 895 W kg –1 ) …”

“…This result is further verified by the high-resolution spectrum of C 1s. Figure f shows the C 1s spectrum which shows that the peaks located at 284.7, 285.7, 286.5, 288.0, and 289.2 eV are ascribed to CC, CN, C–O, CO, and COO bands, respectively . These results demonstrate that core–shell FeCoS 2 /NG is successfully prepared.…”

Cooperative catalysis of Zn3(VO4)2/Ni(OH)2/rGO nanosheet arrays advancing highly active O2 reduction and water-splitting

“…22 Similarly, as shown in Fig. S9 [23][24][25][26][27][28] In addition, the positive shift of metal-oxygen (M-O) in binding energy linked to Zn 3 (VO 4 ) 2 /Ni(OH) 2 and rGO interactions is due to a change in the atomic coordination number or charge-transfer effects. 29 For Zn 3 (VO 4 ) 2 /Ni(OH) 2 , the respective peaks at 856.0 and 873.7 eV for Ni 2p 3/2 and Ni 2p 1/2 , are accompanied by the respective satellites at 861.6 and 879.9 eV, which can be ascribed to the characteristic peak of Ni 2+ (Fig.…”

“…As expected, compared with Zn 3 (VO 4 ) 2 /Ni(OH) 2 , three distinct peaks (H–OH, CO, and C–O) appear in the Zn 3 (VO 4 ) 2 /Ni(OH) 2 /rGO nanosheet arrays, which proves that Zn 3 (VO 4 ) 2 /Ni(OH) 2 nanosheets are successfully loaded onto the rGO support. 23–28 In addition, the positive shift of metal–oxygen (M–O) in binding energy linked to Zn 3 (VO 4 ) 2 /Ni(OH) 2 and rGO interactions is due to a change in the atomic coordination number or charge-transfer effects. 29 For Zn 3 (VO 4 ) 2 /Ni(OH) 2 , the respective peaks at 856.0 and 873.7 eV for Ni 2p 3/2 and Ni 2p 1/2 , are accompanied by the respective satellites at 861.6 and 879.9 eV, which can be ascribed to the characteristic peak of Ni 2+ (Fig.…”

A binary composite La(OH)3@Ni(OH)2 nanomaterial on carboxyl graphene for an efficient hybrid supercapacitor electrode

“…However, the cycling stability of these electrodes was limited to 500 cycles, indicating that further research is needed to improve the cycling stability of these electrodes. To further improve the electrical conductivity and cycling stability of Ni(OH) 2 -based electrodes, some researchers have coupled them with carbon nanotubes, graphene, [17][18][19][20][21][22][23] transition metal oxides, 24 polyaniline, 25,26 and polypyrrole. 27 Nowadays, there are various methods to prepare these composite electrodes, including spin-coating technique, 28 hydrothermal method, 29 electrospinning method, 30 and sol-gel method, 31 and so on.…”