Preparation,Modification And Properties Of Nickel Oxide As Lithium-ion Battery Anode Material

The application of rechargeable lithium-ion batteries with high power and energy densities in electric vehicles is an ideal method to improve the environmental pollution.NiO is considered to be one of the most promising lithium-ion battery anode materials due to its high theoretical capacity,low cost,rich in natural resources.However,the commercial application of NiO has been limited due to its structural entanglement which cause carriers can not move inside.At present,this problem can be solved by doping or coating.Therefore,doping method is employed to improve the electronic conductivity of NiO which enhances the electrochemical performance.The specific research contents are as follows:NiO is prepared by homogeneous precipitation method and modified by Cu doping.The samples are characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）and tested by elecrochemical testing.The results indicate that NiO electrode with the doping ratio at 8:1 exhibits the best electrochemical performance among the modified samples,the discharge capacity of this sample reaches 384.3mAh·g^-1 at 1C.The discharge capacity still remains at 341mAh·g^-1 after 50 cycles at 0.1C.NiO nanosheets are directly grown on the copper foil substrate by hydrothermal method and modified by Cu doping.XRD,ICP and X-ray photoelectron spectroscopy（XPS）are employed to characterize the structure of the samples;SEM and transmission electron microscope（TEM）are used to characterize the morphology.The results indicate that all the modified samples show the nanosheet-like structure and the thickness of the samples are less than 100nm.The lithium-ion half-cells are tested by elecrochemical measurements.Among the modified samples,NiO electrode with the doping ratio at 8:1 exhibits the best electrochemical performance.The discharge capacity of this sample reaches 622.4mAh·g^-1 at 1C and the discharge capacity still remains at 670mAh·g^-1 after 50 cycles at 0.1C.The effect of calcination temperature on the properties of NiO-Cu-8-1 sample is investigated and it is found that the optimum calcination temperature is 400℃.NiO is directly grown on the copper foil substrate by hydrothemal method and modified by Co doping.It can be found that all the diffraction peaks for the modified samples are well exactly matched with the cubic NiO structure from their XRD results.The results of SEM indicate that the modified samples display a spherical structure which is assembled by nanosheets.According to the electrochemical testing,the NiO-Co-10-1 sample exhibits the best electrochemical performance and the discharge capacity still keeps at 458mAh·g^-1 after 50 cycles at 0.1C.The effect of calcination temperature on the properties of NiO-Co-10-1 sample is also investigated and it is clear that the optimum calcination temperature is 400℃.