氧化镍、氧化钒微纳结构的控制及在储能方面的研究
发布时间：2019-06-17 16:20
【摘要】：由于环境污染和能源危机问题日益突出,风能、太阳能等产生的电能需要高效存储,以及便携式电子器件和电动汽车行业的快速发展,开发廉价、高效、环境友好、体积小和质量轻的储能装置是各国研究者面临的重要挑战。像锂离子电池和超级电容器这样的储能器件满足上述各项要求,成为目前研究的热点。而高性能的锂离子电池和超级电容器的实现强烈依赖于电极材料的合理设计。其中,氧化镍是一种赝电容机制的储能材料,具有较高的理论比容量,在超级电容器领域被广泛研究。而五氧化二钒作为一种锂离子电池的正极材料,具有脱嵌锂的存储机制和高的能量密度,也是锂离子电池电极材料近年来的研究热点。这两种材料都具有储量丰富,价格低廉的共同优点。但是作为过渡金属氧化物,电导率低,循环稳定性差的缺点限制了他们的广泛应用。研究发现:如果将纳米技术引入到电极材料的制备,对材料结构进行合理地设计,对于提高超级电容器和锂离子电池的性能具有重要的意义。在本文中,我们旨在用简单的方法合理设计和制备高性能超级电容器和锂离子电池电极材料,为电极材料的发展提供有益的探索。本文的主要内容如下:(1)采用水热法合成了氢氧化镍前躯体,通过调控溶液的ph值变化来调控不同形貌的前躯体。最后煅烧前躯体获得了一系列不同形貌、不同比表面积和孔径分布的蜂窝状nio分级结构。电化学测试结果证实:nio电极表现出优异的电容性能。在1ag-1的电流密度下,可提供1250fg-1的比容量;在5ag-1电流密度时,容量仍保持在945fg-1。当循环3500圈后,容量保持率高达88.4%。该结构之所以有较优异的电容性能,与其高的比表面积,多的介孔含量以及大的孔容有较大关系。另外,将制备的nio作为电容器正极,用改进的hummers法结合水热还原法制备的rgo作为电容器负极,组装成不对称全电容。通过调节正负极材料质量比例得到性能较好的全电容器器件。该器件可实现23.25whkg-1的能量密度及9.3kwkg-1的功率密度,并可成功点亮led灯。(2)通过溶剂热法,合成了一系列不同形貌结构(包括核壳结构、双壁结构、三壁结构和分级中空结构)的v2o5前躯体材料,并对不同形貌结构材料的形成机理进行了详细的探讨。电化学测试结果证实:分级中空结构v2o5具有优异的电化学性能,在1c(147mag-1)电流密度下,2.5-4.0v电压范围内,可提供146.8mahg-1的比容量(理论比容量为147mahg-1)。当电流密度为20c时,容量可达123mahg-1,循环3000圈后比容量仍能保持在73.5mahg-1。并且该材料在2.0-4.0v电压范围测试时同样表现出优良的循环稳定性。另外,将其与商业化的li4ti5o12组装成全电池,在1.0-2.5v的电压范围内,147mag-1的电流密度下,可提供最高139.5mahg-1的比容量;循环100圈后容量仍保持在106 mA g-1,其性能远远高于所报道的在相同测试条件下V2O5全电池性能。
[Abstract]:Due to the increasingly prominent problems of environmental pollution and energy crisis, the electric energy generated by wind energy and solar energy needs efficient storage, as well as the rapid development of portable electronic devices and electric vehicle industry. the development of cheap, efficient, environmentally friendly, small and light energy storage devices is an important challenge faced by researchers all over the world. Energy storage devices such as lithium-ion batteries and supercapacitors meet the above requirements and become the focus of current research. The realization of high performance lithium-ion batteries and supercapacitors depends strongly on the reasonable design of electrode materials. Among them, nickel oxide is a kind of energy storage material with pseudo-capacitance mechanism, which has high theoretical specific capacity and has been widely studied in the field of supercapacitors. Vanadium pentoxide, as a cathode material for lithium-ion batteries, has the storage mechanism of lithium removal and high energy density, and is also the research focus of lithium-ion battery electrode materials in recent years. These two materials have the common advantages of rich reserves and low price. However, as transition metal oxides, their wide application is limited by their low conductivity and poor cycle stability. It is found that if nanotechnology is introduced into the preparation of electrode materials and the structure of the materials is designed reasonably, it is of great significance to improve the performance of supercapacitors and lithium-ion batteries. In this paper, the purpose of this paper is to design and fabricate high performance supercapacitors and lithium ion battery electrode materials reasonably by simple method, and to provide useful exploration for the development of electrode materials. The main contents of this paper are as follows: (1) the precursor of nickel hydroxide was synthesized by hydrothermal method, and the precursor with different morphology was regulated by regulating the ph value of the solution. Finally, a series of honeycomb nio classification structures with different morphology, different surface area and pore size distribution were obtained. The electrochemical results show that the nio electrode has excellent capacitance performance. At the current density of 1ag-1, the specific capacity of 1250fg-1 can be provided, and at the current density of 5ag-1, the capacity can still be kept at 945fg 鈮，
本文编号：2501114
[Abstract]:Due to the increasingly prominent problems of environmental pollution and energy crisis, the electric energy generated by wind energy and solar energy needs efficient storage, as well as the rapid development of portable electronic devices and electric vehicle industry. the development of cheap, efficient, environmentally friendly, small and light energy storage devices is an important challenge faced by researchers all over the world. Energy storage devices such as lithium-ion batteries and supercapacitors meet the above requirements and become the focus of current research. The realization of high performance lithium-ion batteries and supercapacitors depends strongly on the reasonable design of electrode materials. Among them, nickel oxide is a kind of energy storage material with pseudo-capacitance mechanism, which has high theoretical specific capacity and has been widely studied in the field of supercapacitors. Vanadium pentoxide, as a cathode material for lithium-ion batteries, has the storage mechanism of lithium removal and high energy density, and is also the research focus of lithium-ion battery electrode materials in recent years. These two materials have the common advantages of rich reserves and low price. However, as transition metal oxides, their wide application is limited by their low conductivity and poor cycle stability. It is found that if nanotechnology is introduced into the preparation of electrode materials and the structure of the materials is designed reasonably, it is of great significance to improve the performance of supercapacitors and lithium-ion batteries. In this paper, the purpose of this paper is to design and fabricate high performance supercapacitors and lithium ion battery electrode materials reasonably by simple method, and to provide useful exploration for the development of electrode materials. The main contents of this paper are as follows: (1) the precursor of nickel hydroxide was synthesized by hydrothermal method, and the precursor with different morphology was regulated by regulating the ph value of the solution. Finally, a series of honeycomb nio classification structures with different morphology, different surface area and pore size distribution were obtained. The electrochemical results show that the nio electrode has excellent capacitance performance. At the current density of 1ag-1, the specific capacity of 1250fg-1 can be provided, and at the current density of 5ag-1, the capacity can still be kept at 945fg 鈮，
本文编号：2501114
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