Design,Preparation And Performance Of Nanosized Nickel-Based Electrocatalysts And Energy Storage Materials

The increasingly serious energy crisis and environmental pollution have become major problems,which will hinder the economic development and improvement of people's living standards.Therefore,it is urgent to develop green energy materials and technologies.However,using water electrolysis to produce hydrogen and lithium ion batteries are two important research directions for renewable energy and efficient energy storage,respectively.Two typical NiFe₂O₄ and NiCo₂O₄ were selected for Ni-based oxide materials,and their applications in electrocatalytic oxygen evolution reaction?OER?and lithium ion batteries were explored.Herein,Specific research contents of this work include the following aspects:1.An electrocatalyst for oxygen production based on nickel-iron mixed oxide was designed.Nickel-iron mixed oxides were synthesized by doping iron-based Prussian blue with nickel.The influence of different nickel doping amounts and different annealing temperatures on the microstructure and electrocatalytic performance of the electrocatalyst were studied by XRD,XPS,SEM,TEM and electrochemical tests.Experimental results show that,the particle size of as-synthesized nickel-iron mixed oxides range between 20¹50 nm and existing high surface oxygen defects after calcination.The porous metal oxides consisting of nickel oxide and nickel ferrite exhibited the remarkable electrocatalytic property toward OER in an alkaline solution?1 M KOH?,which can be attributed to the nanosized and porous structure,the co-existence of spinel NiFe₂O₄ and cubic NiO,the high content of surface oxygen vacancies.The onset potential of 270 mV and overpotential of 370 mV at 10 mA cm^-2was obtained,respectively.It also shows faster reaction kinetics with Tafel slope of only 48 mV dec^-1.2.Biomass derived-carbon materials were used to synthesize carbon/NiCo₂O₄composites for lithium ion battery anodes.The carbonized pomelo peels?PPC?act as precursor of carbonaceous material,NiCo₂O₄ was uniformly distributed on the surface of carbonized pomelo peels by a hydrothermal method to form PPC/NiCo₂O₄ composite.The experiment shows that the lithium storage properties and stability can be effectively improved by combining NiCo₂O₄ with PPC.The reversible capacity was as high as 522 mAh g^-1at the current density of 50 mA cm^-2.This composite delivers a high reversible capacity of 473.7 mA h g^-1.A long cycle life of up to 1100 cycles at 2000 mA g^-11 is achieved with the retention capacity of 363 mA h g^-1,showing good stability and excellent rate performance.