Synthesis And Electrochemical Performance Of NiO/Expanded Graphite As Anode Materials For Rechargeable Battery

Energy is related to the survival and development of human society.At present,energy development is facing great challenges.With the development of electric vehicles and hybrid vehicles,the requirements for rechargeable batteries are particularly demanded.For lithium ion and sodium ion batteries,the traditional anode materials limit the further improvement of battery performance,to a certain extent.One of the solutions is looking for the anode materials with more advantages.Nickel oxide is one of the candidates for the next generation rechargeable batteries of anode materials owing to its low cost,environmental benignity and high theoretical specific capacity.In this paper,the nickel-based materials with enhanced electrochemical performance by simple synthesis method were studied.In this paper,a ball-milling method was utilized to reduce the size of the materials and well mixed the raw material of nickel hydroxide with four different carbon sources?citric acid monohydrate,carboxymethyl cellulose,gum arabic powder and expanded graphite?,respectively.The morphologies and structures of NiO-C were characterized by XRD,Raman,TGA,SEM,TEM and XPS.And the electrochemical properties of the composites were also tested by galvanostatic charge/discharge,CV,EIS and so on.The results show that the NiO-C-4 prepared by using the expanded graphite as carbon source possesses the best performance.The discharge capacity of the shell-like NiO-C-4 was 977.5 mAh g^-11 after 50 cycles at 200 m A g^-11 at room temperature.The reversible capacity remained at 195.0 mAh g^-11 after 50 cycles at 100mA g^-11 at-25°C and 440.6 mAh g^-11 at 1000 mA g^-1 at 85°C.The NiO-C-4 composites which have the better performance among the lithium ion batteries were studied again as anode materials for sodium ion batteries.The size of Na⁺is higher than that of Li⁺about 25%which make it difficult to embed into the material and reduced the migration speed of sodium ion and reaction speed.However,the material presented a reversible capacity of 430.3 mAh g^-11 after 30 cycles at 100mA g^-11 at ambient temperature and 398.5 mAh g^-1 after 50 cycles.The effects of the order of milling and heating and different carbon content on the electrochemical performance are studied.It was found that the best material is NiO-C-4.