Composite material of nickel hydroxide/graphene or graphite and preparation method for composite material

Abstract

The invention discloses a composite material of nickel hydroxide / graphene or graphite which is structurally Ni(OH)2 / graphite or layered Ni(OH)2 / graphene composite material alternated with Ni(OH)2 and graphene, wherein the weight content of the nickel hydroxide is 10-90%. The invention further discloses a method for preparing the composite material. The composite material is simple in process, low in cost, environment-friendly and easy for batch production.

Description

technical field [0001] The invention relates to a composite material of nickel hydroxide / graphene or graphite. [0002] The invention also relates to a method for preparing the composite material described above. Background technique [0003] Supercapacitors have the advantages of high power density, short charging and discharging time, and environmental friendliness, and are widely used to store solar energy, wind energy, and small electronic devices. With the increasing global environmental requirements and the increasing scarcity of fossil energy, supercapacitors are considered as power sources for next-generation vehicles. However, it is unavoidable that supercapacitors still face two major challenges: one is that the energy density is low, which is not enough to support the long-distance operation of the car; the other is that the price is relatively expensive. This is mainly because most of the existing supercapacitor electrode materials use activated carbon, and its...

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Problems solved by technology

However, the disadvantage of this method is that it is difficult to prepare in batches and time-consuming.

[0011] It has been reported that Ni(NO 3 ) 2 As a nickel precursor, 0.5mg of Ni(OH) was directly electrodeposited on the foamed nickel 2 , 4A g -1 The specific capacitance is 3152F g -1 , but its specific capacitance lost 48% after 300 cycles

It has been reported that graphene vertically arranged on nickel foam was prepared by enhanced plasma chemical vapor deposition, and then Ni(OH) was electrodeposited on the graphene sheet by constant current deposition. 2 nanoparticles to obtain Ni(OH) 2 uniformly distributed on the graphene surface, the Ni(OH) 2 / graphene composite active material utilization rate is high, 2.3A g -1 The specific capacitance is 2215F g -1 , 23.1 A g -1 The specific capacitance is 1305F g -1 , and under this condition, the specific capacitance can still maintain 77% after 2000 constant current charge and discharge cycles, but the preparation process is more complicated and the mass of active material per unit area is only 0.43mg

It has been reported that CNT / NiO was prepared by pulse current deposition method. x (OH) y , the highest specific capacitance after heat treatment is 1451F g -1 , they also compared with CNT / NiO prepared by galvanostatic deposition x (OH) y The properties were compared and found that NiO prepared by pulse current deposition method x (OH) y The particle size is smaller and the electrochemical performance is higher, but it can be seen from its cyclic voltammetry curve that the reversible charge-discharge performance of the material is poor

[0012] The main challenges facing supercapacitors at present are low energy density and high price

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