四氧化三钴作为一种超级电容器电极材料，具有极高的理论比电容和较好的水热合成强度。二氧化锰纳米薄片，具有极高的比表面积。四氧化三钴和二氧化锰的复合结构展现出了优异的综合电化学性能。但关于二氧化锰在四氧化三钴表面的生长过程和形貌控制方法的研究较少。本论文在泡沫镍上合成了电化学性能优良的四氧化三钴纳米线。比较了二氧化锰，四氧化三钴和四氧化三钴-二氧化锰核壳结构的超级电容器性能。经过优化过的四氧化三钴-二氧化锰核壳结构纳米线在电流密度为1 A/g时具有1646 F/g的比电容。同时展现出最低的界面阻抗。阻抗谱显示包围在四氧化三钴周围的二氧化锰纳米片在降低阻抗的过程中扮演重要角色。在水热反应过程中，高锰酸钾溶液的浓度对四氧化三钴-二氧化锰核壳结构的最终形貌有可控的影响，这个影响会导致不同的电化学性能。本文研究了四氧化三钴-二氧化锰电极形态和超级电容器性能之间的关系，最优的高锰酸钾浓度大约为0.015 M. 孔径分布结果显示，用0.015 M高锰酸钾制备的样品中含有较多的孔径较大的孔，这促进了电解液离子的传输。此外，由于四氧化三钴具有导电能力不强，循环稳定性较差等劣势，本论文尝试结合二硫化钼类石墨烯结构的优良离子导电率和循环稳定性，设计并制作了硫化镍@二硫化钼@四氧化三钴三元复合超级电容器材料，并初步研究了其性能。
As a kind of supercapacitor electrode material, Co3O4 has an extremely high specific capacitance and a relatively good hydrothermal intensity. MnO2 nanosheet, has relatively high specific surface area. Co3O4@MnO2 nanowire core-shell structure exhibits excellent comprehensive electrochemical properties. But there are less research focusing on the forming process of MnO2 growing on Co3O4 surface and the morphology controll method of it.This work successfully synthesized Co3O4 nanowire arrays on nickel foam with good electrochemical property. The supercapacitor performances of MnO2, Co3O4 nanowire and Co3O4@MnO2 core-shell structure are compared, and optimized Co3O4@MnO2 core-shell nanowire arrays present the highest specific capacitance of 1646 F g-1 at a current density of 1 A g-1 and lowest interfacial charge transfer resistance. The impedance spectroscopy clearly shows the MnO2 nanosheets surrounding Co3O4 nanowire play an important role in reducing the resistance. During the hydrothermal process, the concentration of KMnO4 solution has a significant effect on the final morphology of Co3O4@MnO2 core-shell structure which is controllable and shows quite different electrochemical property. The relationship between morphology and supercapacitor behavior is studied, and the optimal concentration of KMnO4 solution is approximately 0.015 M. The pore size distribution shows that the sample synthesized in 0.015 M KMnO4 solution has the highest percentage of relatively larger poles, which facilitate the electrolyte ion transfer. What’s more, bare Co3O4 has low conductivity and poor cycling stability. This work aims to use MoS2 to overcome these shortcomings. The ternary material of Ni3S2@MoS2@Co3O4 was designed and prepared. And the electrochemical property of it was preliminarily studied.
