Preparation And Capacitance Properties Of Vanadium Oxide Based-carbonized Bacterial Cellulose Composite Materials

Vanadium oxides such as V₂O₅,VO2,V2O3,andVO have rich valence states from the highest state?+5? to the lowest state?+2?.They have been a better electrode materials due to their unique layered structure.The valence bond in the inner-layer is covalent bond and the inter-layer is molecular forces or hydrogen bond,similar to that of grapheme.The atoms and molecular can de-intercalation between the inter-layer.Research shows that,vanadium oxides have large theoretical specific capacity and they were low cost.But they have obvious drawbacks include low electrical conductivity and unstable structure that will cause poor ion transport efficiency and cyclic stability.So its important to improve these properties of vanadium oxides.In this thesis,carbonized bacterial cellulose?CBC? which has a three-dimensional network structure and good electrical conductivity was used to combined with V₂O₅ and VOOH.We design two composites with different structure configuration.Then we investigate the electrochemical performance of the composite.The major research works are as follows:?1?.The V₂O₅-CBC composite is synthesized by a hydrothermal method.V₂O₅ is belts-like with a width about 60nm and length of several micrometers.CBC is coated at the surface of V₂O₅ nanobelt with a network structure.Forming a belt and network crosslinking structure.Then used as a work electrode and test its capacitance performance in 2M KC1 solution.A specific capacitance of 268Fg-1 was obtained at a scan rate of 5mVs-1,with a capacitance retention of 87% when after 2000cycles.?2?.The VOOH-CBC composite is prepared by a hydrothermal method.VOOH is sphere structure with a diameter of 150nm and loaded on the surface of CBC.When used as electrode material for supercapacitor,this composite electrode reveals good performance.The specific capacitance of VOOH and VOOH-CBC are 66.27Fg-1 and 91.71Fg-1 when the scan rate is 5mVs-1.This indicate that the electrochemical properties of VOOH can be improved after the added of CBC.The cycle performance is researched at a current density of lAg-1.It has a retention of 78% when after 1000 cycles.