Preparation And Study Of Supercapacitor Electrode Materials Based On Molybdates

Supercapacitor?electrochemical capacitors?has become the research hotspot in the field of energy and battery materials because of its high-energy density and high-power density.The molybdates as nickel molybdate and manganese molybdate are gradually introduced into the researches of electrode materials because it can produce rich redox reactions and lead to the higher electrochemical capabilities with its multiple oxidation states.In this paper,composite electrode materials based on molybdates were prepared by hydrothermal method in order to improve the electrochemical performance of the electrode materials and to study the effect of the composite on the properties of the electrode materials.Specific studies are shown as follows:?1?The NiMoO₄ and MnMoO₄ electrode materials were prepared by hy drothermal reaction on the foamed nickel.The morphology of the NiMoO₄ supercapacitor electrode was prepared by stacking the long strip of particles with length of about 250 nm.The specific capacitance of the nanostructured material is 202.12 F g-1 under the condition of 1A g-1.The active material in the MnMoO₄ supercapacitor electrode material was coated on the surface of the foamed nickel with a large lamellar plate,and there was irregular fracture.The nanometer-sized lamellar structure could be observed from the cross section.The calculated specific capacitance is 835.40 F g-1 under 1A g-1.?2?NiMoO₄/MnMoO₄ layered composite materials with NiMoO₄/MnMoO₄ layered composite materials were prepared by hydrothermal method.The NiMoO₄/MnMoO₄ layered composite electrode materials with different proportions were prepared successfully on the foamed nickel.Different electrochemical properties.In particular,the electrode material with a ratio of NiMoO₄/MnMoO₄ of 1: 1 has a specific capacitance of 1248.99 Fg-1 at a current density of 1A g-1,which is about 1.6 times of the specific capacitance of pure MnMoO₄ electrode material prepared by same method and its capacitance can still reach 793.16 F g-1 at current density of 10 A g-1,exhibiting good rate capability.?3?NiMoO₄/Ni Fe-LDHs layered composite materials were fabricated on the foamed nickel substrate by hydrothermal method,and the NiMoO₄/Ni Fe-LDHs layered composite electrode materials with honeycomb structure were successfully prepared.The samples with different ratios had different electrochemical performance.In particular,the electrode material with a ratio of NiMoO₄/Ni Fe-LDHs of 1: 1 has a specific capacitance of 1302.18 F g-1 at a current density of 1A g-1,which is about 6 times of the capacitance of pure NiMoO₄ prepared by the same way.The specific capacitance retention rate is about 77% after 1000 times charge and discharge cycles,showing good electrical performance stability.