Effects Of Different Characteristic Elements On The Electrochemical Performance Of Binary Nickel-based Electrode Materials

In recent years,transition metal compounds have been widely used in energy storage devices.Nickel-based especially compounds as electrode materials have been widely studied because of their many advantages.Compared with a single compound,binary nickel-based compounds have developed many new products because of their more reactive sites and structural stability;however,the binary nickel-based compounds also have defects and deficiencies.By a simple hydrothermal method binary nickel-based compounds(hydrides,oxides,and sulfides)are synthesized,and the third elements with different characteristics are introduced to further improve its electrochemical performance.The basic content mainly includes the followings:(i)Introducing chromium into nickel hydroxide/cobalt hydroxide composites.In the experiment,ternary hydride is synthesized by one-step hydrothermal method,and the effect of chromium content on the morphology and electrochemical properties of binary nickel-based hydride are systematically studied.The results show that with the increasing the amount of chromium,its morphology gradually changes from the original rod shape to the lamellar shape.When the amount of chromium increase,the thickness of the lamellar increases,at the same time,and the specific capacitance of the composite material also increases first and then decreases because of morphology and energy storage mechanism.(ii)Adding gold nanoparticles to nickel oxide/molybdenum oxide.First,a nickel hydroxide/molybdenum hydroxide composite is synthesized by a hydrothermal method,and then calcined in a muffle furnace to convert it into nickel oxide/molybdenum oxide.Finally,gold nanoparticles are introduced into it by in-situ reduction.The results show that the incorporation of gold nanoparticles significantly improves the electrochemical performance of nickel oxide/molybdenum oxide.For this result,the state of electrons during charging and discharging of nickel oxide/molybdenum oxide is analyzed by the band theory of gold nanoparticle incorporation.The results are consistent with the XPS characterization results.This method is expected to be applied to other materials to improve its electrochemical performance.(iii)Adding carbon materials to trinickel disulfide/manganese disulfide.Nickel hydroxide/manganese hydroxide is prepared by hydrothermal method,and then a certain amount of aniline and ammonium persulfate(sulfur source and initiator)are added to it.The products after drying are calcined in nitrogen atmosphere.The final products are composites of trinickel disulfide/manganese disulfide and carbon.The introduction of carbon is mainly to improve the cycle stability and electrical conductivity of the composites.The experimental results also show that the addition of carbon does improve its cycle stability and improve its overall electrochemical performance.