Research On The Preparation Of Transition Metal Nickel And Copper-based Composite Materials And Their Capacitance Performance And Electrolytic Water Performance

With the decrease of fossil fuels and the increase of environmental pollution,the demand for efficient energy storage equipment is growing.Supercapacitor,due to its high power density（about 5 k W/kg）,long cycle life,fast charging/discharging and low maintenance cost,is considered as one of the most important energy storage device and has been applied in backup power systems,portable electronic equipment,telecommunications equipment and vehicles,etc.Electrode material is the key factor affecting capacitance performance,whose development has aroused extensive research interest in energy field.In this paper,the Ni₂B/RGO composite was successfully prepared by a one-step reduction method and the Co-doped Cu-MOF/Cu₂₊₁O composite was also prepared by a reverse synthesis strategy,then both of them were applied as the electrode materials for supercapacitors.Details are as follow:1.A Ni₂B/RGO composite was prepared via a one-step reduction method of nickel dichloride（NiCl₂）and graphene oxide（GO）in ice bath using sodium borohydride（NaBH₄）as reductant under nitrogen atmosphere.The target annealed product Ni₂B/RGO-200 exhibits larger specific surface area,more active sites and higher electrical conductivity,which possesses good capacitive performance.2.A regular star anise-like nonorods structure Co/Cu-MOF/Cu₂₊₁O composite was successfully prepared by a reverse synthesis strategy using Cu（OH）2 as both the template and precursor under the doping of cobalt ions.Due to the large specific surface area provided by array structure and the synergistic effect between double-layer material（Cu-MOF）and battery capacitor material(Cu₂₊₁O),the target product Co/Cu-MOF/Cu₂₊₁O exhibits excellent capacitive properties.Hydrogen is regarded as a promising clean energy due to its high calorific value,extensive sources and green environmental-friendly features.Especially in the 21 st century when new energy develops rapidly,it can be used as a substitute for fossil fuel to meet the growing global energy demand.Electrolysis of water for hydrogen production is an effective method to prepare hydrogen.Therefore,it is of great significance to seek efficient catalysts to promote bipolar reactions（cathodic hydrogen evolution reaction（HER）and anodic oxygen evolution reaction（OER））in water electrolysis.As we know,Pt/C and RuO₂,IrO₂ are the most efficient catalysts for HER and OER,respectively,but their scarcity and high cost seriously hinder their wide applications.Therefore,it is very necessary to study high efficiency and low cost non-noble metal catalysts.In this paper,a nickel phosphide（Nix P）was electrodeposited for HER and nickel borate/graphene（Ni-Bi/RGO）composite was prepared for OER.Details are as follow:1.A flexible NixP material was successfully grown on Ni foam via a co-electrochemical deposition method at NiCl₂ and sodium dihydrogen phosphate aqueous solution.Thanks to the high porosity and conductivity of nickel foam as well as the high catalytic activity and energy storage performance of phosphides,Nix P nanomaterial shows excellent performances for HER and supercapacitor.2.A nickel borate/reduced graphene oxide（Ni-Bi/RGO）composite was prepared via a one-step reduction method of NiCl₂ and GO at room temperature with Na BH₄ as reductant,which shows good performance for OER.