基于海藻酸双金属氧化物气凝胶的锂离子电池负极材料的研究

发布时间：2018-01-09 11:41

本文关键词：基于海藻酸双金属氧化物气凝胶的锂离子电池负极材料的研究　出处：《青岛大学》2017年硕士论文　论文类型：学位论文

【摘要】：高性能锂离子电池需要具有理想微观结构的电极材料,以便实现快速的离子传输,短距离的固态离子扩散,较大的表面积,和较高的电导率。电极材料的微观结构决定了锂离子电池的综合性能。以可再生资源—海藻酸钠为前驱体,制备的双金属氧化物(MTMOs)纳米颗粒和碳纳米管复合而成的高孔隙度三维气凝胶成为研究热点。本论文利用海藻酸通过离子交换过程,可以与金属离子发生螯合,形成特殊的蛋盒‖结构,制备二元金属氧化物杂化气凝胶。在复合气凝胶中,双金属氧化物纳米颗粒通过碳纳米管互相连接,并嵌入碳气凝胶基质中,形成三维网络结构,可以提供大的表面积、缓冲体积膨胀的空间、离子及电子快速传输的路径,从而成为理想的高性能锂离子电池负极材料。本文主要利用海藻酸钠为基质,通过简易的方法制备了具有多孔结构的双金属氧化物/碳纳米管复合气凝胶材料。相比传统的MTMOs/C材料,复合气凝胶材料表现出优异的电化学性能:铁酸钴掺杂碳纳米管气凝胶(CFO/CNT)在0.1 A g~(-1)的电流密度下循环160圈,容量高达1033 m Ah g~(-1);增加至1A g~(-1)循环160圈,容量仍可保持874 m Ah g~(-1)。钴酸锌掺杂碳纳米管气凝胶(ZCO/CNT)在0.1 A g~(-1)的电流密度下循环300圈,容量高达922 m Ah g~(-1);增加至1A g~(-1)循环300圈,容量仍可保持829 m Ah g~(-1)。铁酸锌掺杂碳纳米管气凝胶(ZFO/CNT)在0.1 A g~(-1)的电流密度下循环300圈,容量高达750 m Ah g~(-1);增加至1A g~(-1)循环300圈,容量仍可保持698 m Ah g~(-1)。该优异的性能归因于MTMO纳米颗粒和CNT嵌入海藻酸制备的碳气凝胶基质中,形成三维网状结构,产生的协同效应对电池性能的提高具有重要意义。由此,我们研发了一种高效、环保、经济且可以大规模生产过渡金属氧化物/碳纳米管复合电极材料的新型方法。
[Abstract]:High performance lithium ion batteries need electrode materials with ideal microstructure in order to achieve fast ion transport, short distance solid ion diffusion and large surface area. The composite performance of lithium ion battery is determined by the microstructure of electrode material. The precursor is sodium alginate, a renewable resource. The preparation of bimetallic oxide (MTMOs) nanoparticles and carbon nanotubes (CNTs) composite three-dimensional aerogels with high porosity has become a research hotspot. In this thesis alginate is used through the process of ion exchange. Metal ions can be chelated to form a special egg box structure to prepare binary metal oxide hybrid aerogels. In the composite aerogel, the bimetallic oxide nanoparticles are connected with each other through carbon nanotubes. And embedded in the carbon aerogel matrix to form a three-dimensional network structure, can provide large surface area, buffer volume expansion space, ion and electron fast transport path. Thus it is an ideal anode material for lithium ion batteries with high performance. In this paper, sodium alginate is used as the base material. Bimetallic oxide / carbon nanotube composite aerogels with porous structure were prepared by a simple method compared with traditional MTMOs/C materials. The composite aerogel material showed excellent electrochemical performance: the carbon nanotube aerogel (CFO / CNT) of cobalt ferrate doped with carbon nanotube (CFO / CNT) cycle 160 cycles at the current density of 0.1 A g ~ (-1). Its capacity is as high as 1033mAh / g ~ (-1); Increase to 1 A g / L) cycle 160 laps. The capacity can still be maintained at 874 mAh / g ~ (-1). Zinc cobalt-doped carbon nanotube aerogel (ZCO / CNT) cycles 300 cycles at a current density of 0.1 A g / g ~ (-1). Its capacity is up to 922 mAh / g ~ (-1); Increase to 1 A g / L) cycle 300 laps. The capacity can still be maintained at 829 mAh / g ~ (-1). Zinc ferrate doped carbon nanotube aerogel ZFO-CNT can cycle 300 cycles at a current density of 0.1 A g ~ (-1). Its capacity is up to 750 mAh / g ~ (-1); Increase to 1 A g / L) cycle 300 laps. The MTMO nanoparticles and CNT were embedded in the carbon aerogel matrix prepared by alginic acid to form a three-dimensional network structure. The synergistic effect is of great significance to the improvement of battery performance. As a result, we have developed a kind of high efficiency and environmental protection. A new method for producing transition metal oxide / carbon nanotube composite electrode materials on a large scale.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ427.26;TM912

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