## 5 Applications
### Energy Storage
In another study, nickel oxide and reduced graphene oxide (NiO/rGO) nanocomposite was produced by one step ball milling method. The redox reaction between graphene oxide and nickel led to strong bond formation between them. The nanocomposite exhibited the electrochemical performance with 590 F/g of specific capacitance at 1 A g\({}^{-1}\) of current density and 88% of retention capability at 15 A g\({}^{-1}\) rate. It also exhibited 100% retention after 1000 cycles of charge and discharge. Graphene oxide has been used in few other studies too. Composites of MoS\({}_{2}\)/rGO were used for electrochemical measurements in lithium-ion batteries and supercapacitors by [PERSON] et al. [119]. The interlayers formation of 2D material, enormous active reactive sites, dispersion of MoS\({}_{2}\) nanosheets in to rGO surface and synergistic effect between MoS\({}_{2}\) and rGO in the composite showed negligible discharge capacity decay of 0.2 A g\({}^{-1}\) after 100 cycles and 4 A g\({}^{-1}\) after 5000 cycles for lithium-ion batteries and supercapacitors, respectively. In another study, anode material prepared by the composite of MoS\({}_{2}\)/graphene by [PERSON] et al. showed 95% of retention capacity with a better cycling stability after 250 cycles at current density of 0.3 A g\({}^{-1}\) for the sodium-ion batteries. The density functional theory (DFT) calculation revealed the possibility of activation of functional groups in the MoS\({}_{2}\)/graphene composite. The heterostructures with low degree defects and oxygen residual in graphene improves the conductivity of electrons in composite material and depletion of Na\({}^{+}\) diffusion barrier. The performance of the composite material with few-layered niobium diselenide (NbSe\({}_{2}\)) and graphene synthesized via wet ball milling method (WBMNG) reported by the [PERSON] et al. [123]. The anode material by composite showed 1142 mA h g\({}^{-1}\) of initial capacity and 1000 mA h g\({}^{-1}\) of reversible capacity at 0.1 A g\({}^{-1}\) of current density after 200 cycles in lithium-ion battery. The thin layered graphene with smaller NbSe\({}_{2}\) particles dispersed over it showed an increase in the surface area of the composite material. It also provided an effective electron/ion transport pathway to increase the rate of current in anode material. The layered structure may be responsible for excessive storage capacity. All these properties result in satisfactory electrochemical performance of the WBMNG anode material. The novel structure of N-graphene by performing one step ball milling method by using (calcium carbide) CaC\({}_{2}\) and pyrazine with absolute ethanol reported by [PERSON] et al. [123] showed maximum capacitance of 235 F g\({}^{-1}\) of at 1 A g\({}^{-1}\) of current density and 87% of retention capacitance after 3000 cycles of charge and discharge cycles at 6 A g\({}^{-1}\) current density. In this work, Pyrazine was used as nitrogen precursor. Nitrogen heteroatomic defectsand large surface area fast electron transportation improved electrochemical performance of N-graphene. The properties of layered structured materials with ion conduction studied by the [PERSON] et al. [9] showed an improved ionic conductivity of the electrode material up to \(7\times 10^{-4}\) Scm\({}^{-1}\) by layered-structured materials prepared by the high energy ball milling technique. The effect of annealing the precursor at low temperature led to phase transition of material with increased defects and disorders resulting in good energy storage capabilities. In another work electrochemical performance of the ball milled (BM) and manually ground (MG) layered Li\({}_{1.02}\)Ni\({}_{0.4}\)Co\({}_{0.2}\)Mn\({}_{0.4}\)O\({}_{2}\) material with carbon powder was investigated by [PERSON] et al. They reported that the BM sample exhibited better electrochemical performance than the MG sample. The retention capacity was calculated to be 87 and 75% for BM and MG sample respectively at 8C. The conductivity of the layered oxide material was enhanced by adding the carbon powder.