Amorphous mesoporous nickel phosphate/reduced graphene oxide with superior performance for electrochemical capacitors

Abstract

Nickel phosphate (Ni(PO)) is a promising electrode material for electrochemical capacitors, but the low intrinsic electrical conductivity and poor rate capability of Ni(PO) are the main challenges. To tackle these problems, amorphous mesoporous Ni(PO) with a pore diameter of 2-10 nm is grown on reduced graphene oxide (rGO), and a Ni(PO)/rGO composite is obtained via a facile hydrothermal-calcination method in this work. The Ni(PO)/rGO composite calcined at 300 °C (Ni(PO)/rGO-300) possesses a uniform particle size and a high specific surface area of 198.72 m g. Benefiting from the structural characteristics, the synergistic effect of components and the high specific surface area, the Ni(PO)/rGO-300 composite exhibits an extremely high specific capacitance of 1726 F g at 0.5 A g and an excellent rate capability of 850 F g at 25 A g. In addition, the assembled Ni(PO)/rGO-300//activated carbon asymmetric electrochemical capacitor delivers a good energy density of 57.42 W h kg at a power density of 160 W kg. Compared with Ni(PO)/rGO composites calcined at other temperatures and other nickel-phosphorus compounds reported in the literature, the Ni(PO)/rGO-300 composite containing amorphous mesoporous Ni(PO) exhibits superior electrochemical performance, representing a new kind of electrode material for electrochemical capacitors.

Composites of NiS2 Microblocks, MoS2 Nanosheets, and Reduced Graphene Oxide for Energy Storage and Electrochemical Detection of Bisphenol A

“…NiS 2 /MoS 2 /rGO nanocomposite was synthesized as shown in Scheme . Graphite oxide (GO) was synthesized by the modified Hummers’ method. − GO colloid (0.74 mL, 4 mg mL –1 ) and 0.03 g of as-prepared MoS 2 were ultrasonically dispersed in 20 mL of distilled water, respectively. Then, 0.03 g of MoS 2 was added to the GO suspension with stirring; 0.076 g of NiCl 2 ·6H 2 O and 0.10 g of CH 4 N 2 S were added to the mixed solution and dissolved completely.…”

Prelithiated, Multiscale Nickel Phosphate Octahydrate Platelets by a Tailored Nanoarchitectonics Approach

“…When added to amorphous mesoporous nickel phosphate, a superior electrode material for electrochemical capacitors was achieved, reaching higher specific capacitance of 1726 F g −1 at 0.5 A g −1 , more than double its carbon-free counterpart. 23 Nanoparticles with tailored geometry offer improved electrochemical performance with regard to higher lithium solubility and gravimetric capacity as well as enhanced fracture toughness and fatigue resistance. 7,11,25,26 The sonochemical approach has acquired therein considerable significance considering the environmentally benign and low-cost conditions, while enhancing the chemical reactivity.…”

“…Another challenge associated with nickel phosphates is their poor electrical conductivity. In that regard, the addition of a conductive component has been utilized and proven to enhance the electrochemical performance. , Recently, a carbon-coated bimetallic cobalt-nickel phosphate octahydrate electrode in a Zn battery revealed an increase of the capacitive contribution as well as improved rate performance and cycling stability (enhancement of the capacity retention by 1/3) . Alternatively, reduced GO sheets can be incorporated in the electrode material to increase the intrinsic electrical conductivity and simultaneously contribute to the capacitance, synergistically enhancing the electrochemical performance.…”

Co-doped amorphous NiMoS4 modified with rGO for high-rate performance and long-cycling stability of hybrid supercapacitors

“…[6][7][8][9] The unique amorphous structure of NiMoS 4 can provide more ion diffusion channels, which can bring about excellent electrochemical performance. 10 In NiMoS 4 -based supercapacitors, charge storage occurs in the bulk phase as opposed to the surface, which is susceptible to issues such as sluggish charge-discharge rates and extreme voltage polarization. Nanostructured engineering with reduced graphene oxide (rGO) is an effective strategy for optimizing the nanostructure and enhancing the electrochemical activity of the electrode material.…”