Controllable Preparation And Energy Storage Properties Of Co₃O₄-blased Nanocomposites

Recently,the development of clean energy,storage and transformation technology research is particularly urgent in China.It is found that those transition metal oxides as a negative material can be designed and other valuable advantages such as the low price and excellent performance.At the same time,the metal organic framework(MOFs)is an excellent precursor to synthesis anode materials with a high specific surface area and porosity.Therefore,Co3O4-based nanomaterials were prepared,further synthesing Co3O4@rGO nanocomposites.And the morphology of Co3O4/ZnFe2O4/C nanocomposites with heterojunction was investigated on MOFs-derived structures.Mainly completed work as follows:1.Preparation of Co3O4 and Co3O4@rGO Nanocomposites by solvothermal method and the electrochemical performance testsThe Co3O4 nanosheets with atomic thickness were prepared by solvothermal method.The reduction of grapheme oxide(GO)and the coating of Co3O4 by reduction Graphene Oxide(rGO)were carried out with cetyltrimethylammonium bromide(CTAB)used as surfactant after calcinations at room temperature.GO turns into rGO.The performance of Co3O4@rGO have a great improvement when compared with Co3O4.When applied on lithium-ion battery,Co3O4@rGO provides an initial discharge capacity of 1462.0 mAh g-1 at 200 mA g-1.After 130 cycles,it maintains a high capacity retention rate of 78.6%(879.6 mAh g-1).When applied on supercapacitor,at different current densities from 0.5 A g-1 to 3 A g-1,with specific capacitance of Co3O4 rising from 250.2 F to 320.6 F,Co3O4@rGO goes from 356.3 F to 358.9 F.Besides,the specific capacitance of the Co3O4@rGO nanosheet can maintain an initial value of 92%and still maintain 89%capacity after 3000 cycles.2.Preparation of Co3O4/ZnFe2O4/C hollow core heterojunction nanocomposites which deprived from MOFs by solvothermal method and the electrochemical performance tests.Because of the synergistic effect of the heterostructure,ZnFe2O4/C was prepared by a simple solvothermal method;further synthesing Co3O4/ZnFe2O4/C heterojunction composites for furthering improved the performance of the two-dimensional Co3O4 nanosheet.By adjusting the molar ratio of reactants,temperature and time,morphology and its growth mechanism were studied.The result shows that ZnFe2O4/C derived from MOFs had synthesized a uniform hollow shell structure,and it could further contribute to forming Co3O4/ZnFe2O4/C heterojunction nanocomposite.Compared with ZnFe2O4/C and Co3O4/ZnFe2O4/C as electrode materials,Co3O4/ZnFe2O4/C is superior to ZnFe2O4/C in electrochemical performance test.ZnFe2O4/C is slightly reduced from 361.2 F g-1 of 0.5 A g-1 to 279.0 F g-1 of 3 A g-1,while ZnFe2O4/C decreases from 309.9 F g-1 to 230.71 F g-1.