Reduced graphene oxide/nickel cobaltite nanoflake composites for high specific capacitance supercapacitors

Urchin and sheaf-like NiCo 2 O 4 nanostructures: Synthesis and electrochemical energy storage application

“…When compared to simple metal oxides, mixed metal oxides exhibit high electrical conductivity due to lower activation energy for electron transfer between cations [3,18]. A number of single phase binary metal oxide systems such as CuFe 2 O 4 [19], NiMn 2 O 4 [20], MnFe 2 O 4 [21,22], ZnCo 2 O 4 [23], MnCo 2 O 4 [24], CoFe 2 O 4 [25,26], NiCo 2 O 4 [27,28], and their composites CoFe 2 O 4 /graphene [29], NiFe 2 O 4 /PANI [30], NiCo 2 O 4 /graphene [31,32], NiCo 2 O 4 /CNT [33] and NiCo 2 O 4 /carbon cloth [34] have been reported. Among these oxides, the spinel NiCo 2 O 4 has been emerging as high performance electrode material for ECs.…”

Synthesis and remarkable capacitive performance of reduced graphene oxide/silver/nickel-cobalt sulfide ternary nanocomposites

“…Compared with zero-dimensional carbon nanoparticles and one-dimensional carbon nanotubes, graphene with two-dimensional structure is easier and more flexible to integrate with other components. Graphene/metal oxides or sulfides composite electrodes have been widely investigated recently [23][24][25]. It is found that the introduction of graphene as a flexible matrix could effectively improve the electrochemical performance of active components.…”

One-pot electrodeposition synthesis of ZnO/graphene composite and its use as binder-free electrode for supercapacitor

“…Worth the whistle, even at a high scan rate of 50 mVs -1 , the redox peaks are also observed, revealing that the resulting composite active materials are beneficial to fast redox reaction. [9,45] As shown in Figure 4 (a), to further evaluate the electrochemical capacitance of the obtained samples, galvanostatic charge-discharge tests are performed at a serious of current densities within the potential range of from 0 to 0.5 V. Distinctly, the discharge curves contains a first potential drop produced by the internal resistance of electrode and the subsequent evident plateau region accused by pseudocapacaitive behavior, [46,47] showing the characteristic of pseudo-capacitance, which is agreed with the results of CV tests and is distinct from the curves of electrical double layer capacitors with nearly linear plots. [43] The specific capacitance for electrodes can be At a current density of 3 Ag -1 , the resulting hybrid electrode presents a high specific capacitance of 291 Fg -1 , which is significantly higher than those of pure ZnO (118.8…”