The Synthesis Of Ni-Based Double Metal Oxide And Graphite Nano-Flakes Composites For Supercapacitor Applications

Nickel-based double mental oxides are ideal supercapacitor electrode materials with excellent theoretical specific capacity and low price,but the poor cycle stability limits its application.Graphite nano-flakes are carbon materials composed of a few number layers(about 10 layers)graphene.They are similar with graphene but have lower cost so they have been widely used in recent years.In this paper,the nickel-based double mental oxide/graphite nano-flakes composite were synthesized.It not only had the better electrochemical properties,but also used a simple synthesis method which can realize the functionalization of graphite nano-flakes in industry.The main contents were as follows:(1)In this paper,a uniform dispersion nickel-cobalt oxide/graphite nano-flakes composites was obtained by hydrothermal-calcination method(Co1.29Ni1.71O4/GNF).First,nickel salt and cobalt salt were deposited on the surface of the graphite nano-flakes with urea as a precipitant to obtain the nickel-cobalt hydroxide/graphite nano-flakes composite,and the composite was subjected to high-temperature to obtain a final product.The electrochemical measurements were conducted by a three-compartment cell and two-electrode cell.The specific capacity of the material was 1332 F g-1 at the current density of 1 A g-1.After 3500 cycles,the capacity retention of the material was 80%,showing better long cycle stability.After testing with a two-electrode cell,the specific capacity of the material is 94.3 F g-1.When the power density is 1600 W kg-1,the energy density can reach 26.8 Wh kg-1.(2)A nickel-manganese oxide/graphite nano-flakes composite(MnNi2O4/GNF)was prepared by a simple one-step hydrothermal method.The composite had high specific surface area and excellent electrochemical performance.The method used nickel salt,manganese salt,potassium permanganate and graphite nano-flakes as raw materials,nickel and cobalt metal were uniformly dispersed on the surface of the graphite nano-flakes.The electrochemical measurements were conducted by a three-compartment cell and two-electrode cell.The specific capacity of the material was 1644 F g-1 at the current density of 1 A g-1.After 3000 cycles,the capacity retention of the material were 93%,showing better long cycle stability.After testing with a two-electrode cell,the specific capacity of the material was 64 F g-1 at a current density of 1 A g-1.When the power density was 800 W kg-1,the energy density can reach 25.1 Wh kg-1.Finally,the economic calculation of nickel-manganese oxide/graphite nano-flakes composites was carried out.The analysis results showed that the preparation process cost of the composites was lower.The price advantage of nickel-based metal oxides and graphite nano-flakes were fully utilized.It had better electrochemical performance index,this composite material can have a good application prospect and market value.