一维微纳结构锂离子电池钴基电极材料的制备及电化学性能研究
发布时间：2019-06-07 11:53
【摘要】：锂离子电池因为环境污染和能源危机等问题越来越严重而在人们日常生活中扮演着越来越重要的角色。但是以磷酸铁锂等为正极、石墨为负极的传统锂离子电池因为能量密度和功率密度较低等因素逐渐无法满足人们对下一代锂离子电池的需求。因此,发展新型的锂离子电池材料、对材料进行改性及构建新型全电池具有重要研究意义。本文的主要内容包括以下几个方面：1、采用一种简单的分步沉淀法分别制备了一维微纳层状结构富锂Li0.2Ni0.13co0.13Mno.54O2正极材料,高镍LiNi0.8Co0.15Al0.05O2正极材料和尖晶石型CoMn2O4负极材料。一维Li1.2Ni0.13Co0.13Mn0.54O2微米棒展现了出色的电化学性能。其在0.1 C下首次放电容量达到300 mAhg-1,库伦效率为86%,在2C倍率下循环100次容量保持率为90%,在10C高倍率下放电仍有127.7 mAh.g-1的放电容量。LiNi0.8CO0.15Al0.05O2微米棒也展现了出色的电化学性能。这主要因为-维微纳结构的电极材料能有效缩短离子扩散距离、提供合适的电极和电解液接触面积并能够有效缓解材料在锂离子脱嵌过程中的应力。为了解决富锂材料首次库伦效率低的问题,我们将制备的Li1.2Nio.13Co0.13微米棒在偏钒酸铵的水溶液中浸渍烘干,之后进行煅烧,得到Li1.2Ni0.13Co0.13Mn0.54O2-V2O5复合材料,经过改性,Li1.2Ni0.13Co0.13Mn0.54O2正极材料首次库伦效率从86%提高到111%,放电容量也有了很大程度的提高。富锂材料首次库伦效率低的问题得到了有效解决。这主要因为V205是一种电化学活性物质,能与负极的锂生成LixVO3等具有电化学活性的电极材料。2、将制备的Li1.2Ni0.13Co0.13Mn0.54O2微米棒与生长在铜基底上的Fe3O4/Cu阵列薄膜直接组装构建新型Fe3O4/Cu全电池。通过调节正负极容量比为1.1：1不经过对负极的预活化这样不仅可以利用富锂首次的不可逆容量来弥补负极首次形成SEI膜所需的锂量,也省去了预锂化的繁琐步骤。Li1.2Ni0.13Co0.13Mn0.54O2||Fe3O4/Cu全电池在0.1 C倍率下能量密度为230 Wh kg-1,在0.5 C倍率下循环50次能量密度仍能达到196Wh kg-1。
[Abstract]:Lithium-ion batteries play a more and more important role in people's daily life because of the more and more serious problems such as environmental pollution and energy crisis. However, the traditional lithium-ion batteries with lithium iron phosphate as positive electrode and graphite as negative electrode are gradually unable to meet the needs of the next generation lithium-ion batteries because of their low energy density and power density. Therefore, it is of great significance to develop new lithium-ion battery materials, modify the materials and construct a new type of whole battery. The main contents of this paper include the following aspects: 1. One-dimensional micro-nano layered lithium-rich Li0.2Ni0.13co0.13Mno.54O2 cathode materials were prepared by a simple step-by-step precipitation method. High nickel LiNi0.8Co0.15Al0.05O2 cathode material and spinel CoMn2O4 negative electrode material. One-dimensional Li1.2Ni0.13Co0.13Mn0.54O2 micrometer rods show excellent electrochemical performance. The first discharge capacity at 0.1C is 86% at 300 mAhg-1, Coulomb efficiency, and the capacity retention rate for 100 cycles is 90% at 2C rate. There is still a discharge capacity of 127.7 mAh.g-1 at high rate of 10C. LiNi0.8CO0.15Al0.05O2 micrometer rods also show excellent electrochemical performance. This is mainly due to the fact that the electrode material with Vivian micro-nano structure can effectively shorten the ion diffusion distance, provide a suitable contact area between electrode and electrolyte, and can effectively alleviate the stress of the material in the process of lithium ion deintercalation. In order to solve the problem of low Coulomb efficiency of lithium-rich materials for the first time, the prepared Li1.2Nio.13Co0.13 micron rods were soaked and dried in ammonium metavanadate aqueous solution, and then calcined to obtain Li1.2Ni0.13Co0.13Mn0.54O2-V2O5 composites. After modification, the Coulomb efficiency of Li1.2Ni0.13Co0.13Mn0.54O2 cathode material increased from 86% to 111% for the first time, and the discharge capacity was also greatly improved. For the first time, the problem of low Coulomb efficiency of lithium-rich materials has been effectively solved. This is mainly because V205 is a kind of electrochemical active substance, which can form LixVO3 and other electrode materials with electrochemical activity with lithium of negative electrode. 2, The prepared Li1.2Ni0.13Co0.13Mn0.54O2 micron rod and Fe3O4/Cu array film grown on copper substrate were directly assembled to construct a new type of Fe3O4/Cu whole cell. By adjusting the positive and negative electrode capacity ratio to 1.1 鈮，
本文编号：2494773
[Abstract]:Lithium-ion batteries play a more and more important role in people's daily life because of the more and more serious problems such as environmental pollution and energy crisis. However, the traditional lithium-ion batteries with lithium iron phosphate as positive electrode and graphite as negative electrode are gradually unable to meet the needs of the next generation lithium-ion batteries because of their low energy density and power density. Therefore, it is of great significance to develop new lithium-ion battery materials, modify the materials and construct a new type of whole battery. The main contents of this paper include the following aspects: 1. One-dimensional micro-nano layered lithium-rich Li0.2Ni0.13co0.13Mno.54O2 cathode materials were prepared by a simple step-by-step precipitation method. High nickel LiNi0.8Co0.15Al0.05O2 cathode material and spinel CoMn2O4 negative electrode material. One-dimensional Li1.2Ni0.13Co0.13Mn0.54O2 micrometer rods show excellent electrochemical performance. The first discharge capacity at 0.1C is 86% at 300 mAhg-1, Coulomb efficiency, and the capacity retention rate for 100 cycles is 90% at 2C rate. There is still a discharge capacity of 127.7 mAh.g-1 at high rate of 10C. LiNi0.8CO0.15Al0.05O2 micrometer rods also show excellent electrochemical performance. This is mainly due to the fact that the electrode material with Vivian micro-nano structure can effectively shorten the ion diffusion distance, provide a suitable contact area between electrode and electrolyte, and can effectively alleviate the stress of the material in the process of lithium ion deintercalation. In order to solve the problem of low Coulomb efficiency of lithium-rich materials for the first time, the prepared Li1.2Nio.13Co0.13 micron rods were soaked and dried in ammonium metavanadate aqueous solution, and then calcined to obtain Li1.2Ni0.13Co0.13Mn0.54O2-V2O5 composites. After modification, the Coulomb efficiency of Li1.2Ni0.13Co0.13Mn0.54O2 cathode material increased from 86% to 111% for the first time, and the discharge capacity was also greatly improved. For the first time, the problem of low Coulomb efficiency of lithium-rich materials has been effectively solved. This is mainly because V205 is a kind of electrochemical active substance, which can form LixVO3 and other electrode materials with electrochemical activity with lithium of negative electrode. 2, The prepared Li1.2Ni0.13Co0.13Mn0.54O2 micron rod and Fe3O4/Cu array film grown on copper substrate were directly assembled to construct a new type of Fe3O4/Cu whole cell. By adjusting the positive and negative electrode capacity ratio to 1.1 鈮，
本文编号：2494773
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