Preparation And Supercapacitor Performance Of NiCo₂O₄ And Its Composite Electrode Materials

In recent years,many developed and developing countries have adopted researches on supercapacitors as national key research and development projects,which have successfully applied in the fields of electric power,industry,automobile,rail transit,military aerospace,and intelligent electronic products.And significant achievements have been achieved in fuel economy and environmental protection.Electrode materials are important factors to the supercapacitors'performance.Due to the high theoretical specific capacitance,transition metal oxides are usually used as active electrode materials for supercapacitors in aboundent of studies.At present,most of the electrode materials prepared in other researches have shown some shortcomings in performance,which cannot meet the needs of practical applications.Thus,NiCo₂O₄ and its composites electrode materials with high specific surface area,high specific capacitance and high energy density were prepared in this research.The details are as follows:?1?In this research,NiCo₂O₄,NiCo₂O₄@TiO₂ and NiCo₂O₄@MoMnO₄nanoparticles were prepared by hydrothermal method.The structure and morphology tests show that both of the electrode materials have standard crystal form.The tests of structures and morphologies proved that NiCo₂O₄ and two different transition metal oxides composites were successfully compounded respectively.The BET analyses show that the specific surface area of NiCo₂O₄@MoMnO₄ composite electrode material is larger than NiCo₂O₄@TiO₂,and the specific surface areas are 65.25 m²/g and 40.56 m²/g,respectively.In order to study the supercapacitors'performance of the two electrode materials,the prepared electrode materials were tested in three-electrode system and two-electrode system,respectively.?2?Through the tests in the three-electrode system,it is found that the NiCo₂O₄@TiO₂ and NiCo₂O₄@MoMnO₄ composite electrode materials have excellent supercapacitor performance.The test results show that the mass specific capacitance of NiCo₂O₄@TiO₂ and NiCo₂O₄@MoMnO₄ composite electrodes at the current density of 5 mA cm^-2 are 1162.9F g^-1 and 1849.9F g^-1,respectively.In the3000 cycles performance tests,the capacitance retention rates of the two were 95.4%and 92.1%of their initial,respectively.The results show that the composite of NiCo₂O₄ with different transition metal oxides could improve the supercapacitors'performance greatly.?3?In order to further promote the process of supercapacitors'application,the two-electrode systems with NiCo₂O₄@TiO₂ and NiCo₂O₄@MoMnO₄ composite electrode materials as positive electrodes and AC as negative electrode were assembled and electrochemical performance tests were carried out.The test results showthatthespecificcapacitancesofNiCo₂O₄@TiO₂//ACand NiCo₂O₄@MoMnO₄//AC two-electrode systems at current density of 5A g^-1 are255.9F g^-1 and 279.7F g^-1,respectively.And both have higher energy densities:at the power density of 4.0 kw/kg,the energy density are 91.0 wh/kg and 99.5 wh/kg,respectively.The NiCo₂O₄ and its composite electrode materials prepared in this research have large specific surface area,high energy density and excellent electrochemical performance,which are suitable electrode materials for supercapacitor and are showed to be of good application potential and development prospects.