铁系化合物的制备及超级电容性能研究

【作者】 陈洁；

【导师】 黄可龙；

【作者基本信息】 中南大学 ， 应用化学， 2009， 硕士

【摘要】 超级电容器是一种新型储能器件,具有高功率密度、循环寿命长等特点。超级电容器在混合动力电动汽车和移动电子设备的短期电源供应等方面引起了人们的广泛注意。无定形RuO₂χH₂O是目前研究的最为成功的超级电容器电极材料,其具有768F·g^-1的比容量,但材料有毒性,价格昂贵。因此,寻求一种廉价、环境友好且电化学性能良好的电极材料成为科研工作者的研究热点。论文对铁系化合物如Fe₃O₄纳米材料/膜及不溶性普鲁士蓝衍生物作为超级电容器电极材料的电化学性能进行研究,以评估其作为超级电容器电极材料的潜在应用前景。论文的主要内容如下:采用水热法制备了Fe₃O₄纳米颗粒,初步探讨了有机试剂的添加对产物形貌的影响。通过循环伏安、恒流充放电和交流阻抗等测试对Fe₃O₄电极材料的电化学性能进行表征。结果表明,在0.1A·g^-1电流密度下,-1.2～0.2V（υs SCE）电位范围内,球形纳米Fe₃O₄颗粒在1mol·L^-1 Na₂SO₃的溶液中表现出高的比容量(113.01F·g^-1),循环1000次后,容量保持率为72.9%。此外,将电极材料薄膜化,通过简单的水热法在不锈钢薄片上制备Fe₃O₄薄膜,并将其作为超级电容器的电极材料,通过电化学方法检测其超级电容性能。研究结果表明,在6mA的电流密度下,-1～0V的电压范围内,所得的Fe₃O₄薄膜在1mol·L^-1 Na₂SO₃的溶液中表现出118.2F·g^-1的比容量,经过500次循环后比容量仍保持88.75%。通过简单的共沉淀法制备不溶性普鲁士蓝衍生物（Mhcf）,将其作为超级电容器电极材料,探讨其在水溶液体系中的超级电容性能。研究结果表明,电极材料的电容主要为赝电容。由于普鲁士蓝衍生物中不同的金属元素M（M:Fe,Ni,Co）,材料表现出不同的电化学性能,如氧化还原峰电位、氧化还原窗口及电容等。在所研究的材料Mhcf中,在相同的电流密度(0.2A·g^-1)下,Nihcf电极材料表现出较高的比容量(574.7F·g^-1)。此外,不溶性普鲁士蓝衍生物表现出较好的循环稳定性。更多还原

【Abstract】 Electrochemical supercapacitors are charge-storage devices that possess high ideally power density,excellent reversibility and long cycle life,which have attracted a lot of attention in power source applications such as hybrid electric vehicles,short-term power sources for mobile electronic devices.Up to date,amorphous RuO₂·χH₂O was reported as the most promising electrode material for supercapacitor with a specific capacitance of 768 F·g^-1.But the high cost and environmental toxicity of this material limits its extensive use in commercial applications.Efforts have been made to find a cheap and environmental friendly material with good electrochemical performance to replace RuO₂.In this paper,the electrochemical performance of iron-based compounds such as Fe₃O₄ nanoparticles / film and insoluble prussian derivatives were investigated to evaluate their potential application in supercapacitor.The main contents were as follow:Fe₃O₄ nanoparticles were prepared by a simple hydrothermal method. The influence of organic solution on the morphology of as-prepared product was investigated.Meanwhile,the relationship between the morphology of products and their supercapacitor property was also investigated by cyclic voltammetry（CV）,constant charge/discharge test and electrochemical impedance spectra（EIS）.The results showed that compared with products with cubic and wire-like morphology,particles with spherical morphology exhibited higher specific capacity(113.01 F·g^-1) with capacity retention of 72.9%after 1000 cycles in 1 mol·L^-1 Na₂SO₃ solution.Fe₃O₄ film on steel foil was prepared by hydrothermal method.The possible application of Fe₃O₄ film as electrode material of supercapacitor was evaluated.The results showed that in 1 mol·L^-1 Na₂SO₃ solution,the Fe₃O₄ film on steel foil exhibited a specific capacitance of 118.2 F·g^-1 at the current of 6mA between -1 and 0.1 V with capacity retention of 88.75%after 500 cycles.Nano-sized insoluble prussian derivatives（Mhcf） were prepared by a simple co-precipitation method.The potential of using these materials for supercapacitor was examined.The results showed that the capacity of Mhcf mainly resulted from the pseudocapacitive capacitance.The electrodes showed different electrochemical performances such as redox peak potential,potential window and capacity behaviors in aqueous solution,due to the different types of the metal（M） in Mhcf.Among the materials studied,Nihcf electrodes exhibited highest specific discharge capacity(574.7 F·g^-1) under the same current density.The Mhcf electrodes showed good cyclic performance.更多还原