Preparation And Properties Of TiN-based Electrode Materials For Supercapacitor

Supercapacitors is regarded as a new type energy storage device due to the good performance of fast charge and discharge,high energy density,good stability and environmental protection,which can replace the fuel cells and storage batteries.In general,the energy storage method of supercapacitors mainly depends on the electrode materials.Different types of electrode materials exhibit different energy storage mechanisms.Although carbon-based electrode materials have good conductivity and cycle stability,they have low capacity.In contrast,metal oxides have high capacitance,but poor conductivity makes cycle stability lower.Nowadays,transition metal nitrides have attracted widely attention because of their high theoretical specific capacitance,high mechanical stability,and high electrical conductivity.Therefore,in this paper,transition metal nitrides were selected as electrode materials and their electrochemical performance was studied.Among many transition metal nitrides,TiN as an electrode material has attracted great attention for the outstanding electrical conductivity and easy synthesis as well as low cost.Therefore,in this study,TiN nanoparticles,TiN@CN nanocapsules and TiN-NiO composites were synthesized by arc-discharge method and dopamine in-situ self-polymerization method with the titanium metal served as the raw material.The morphology structure,phase composition and the surface chemical composition of the samples was characterized by X-ray diffractometer,Raman spectroscopy,X-ray photoelectron spectroscopy and transmission electron microscopy.In addition,the electrochemical performance was evaluated by electrochemical workstation.TiN@CN nanocapsules were synthesized by arc-discharge method combine with in-situ self-polymerization method.In experiment,the content of CN in the self-polymerization reaction was adjusted by changing the amount of dopamine.The result shown that when the mass ratio of TiN and dopamine is 1:1.5,the electrochemical performance of TiN@CN nanocapsules were optimal,the highest specific capacitance is 119 F g^-1 of the TiN@CN nanocapsules,and the capacitance retention can still retain 92%after 5000 cycles at the current density of 2 A g^-1.The excellent electrochemical performance of TiN@CN nanocapsules is due to the synergy between the carbon shell and the TiN core forms an electron-rich region,which enhances the conductivity of the material and accelerates the electron transport capability.TiN-NiO composites were synthesized by arc-discharge method combined with micro-oxidation treatment with the titanium and nickel metal as raw materials.The as-prepared samples were characterized by ERD and TEM.The TiN-NiO composites were prepared as working electrode,and the electrochemical performance was tested by a three-electrode system.The results shown that the specific capacitance is highest when the NiO compound amount is 3wt%,and the specific capacitance was as high as 1209.1 F g^-1,and the capacitance retention was still reach 80%after 5000cycles.The experiments result show that metal oxides can greatly increase the capacitance of the material,and the good conductivity of TiN can increase the conductivity of the material.The synergistic effect of the metal oxides and TiN improves the electrochemical performance.The research shows that TiN@CN nanocapsules and TiN-NiO composite in this paper all have the advantages of easy availability of raw materials,simple preparation process,and low cost.Importantly,the electrochemical performance of as-prepared samples is greatly improved compared to pure phase TiN.Hences,TiN-based materials is a good promising electrode materials for supercapacitors.