基于聚吡咯碳化的无定形碳材料的制备及其电化学性能研究

发布时间：2019-05-30 03:05

【摘要】：本世纪的关注焦点是资源利用、经济发展和环境保护，而电池技术的发展与三者密切相关。锂离子电池具有高电压、高比容量、绿色环保以及长循环寿命等优势，自1991年问世以来，已在二次电池市场中与镍铬电池、镍氢电池呈三足鼎立的态势。正极材料、负极材料和电解液是影响锂离子电池性能的关键因素。商品化的负极材料——石墨，存在理论容量低等问题，因此开发性能优良的负极材料具有重大意义。硬碳凭借较高的比容量、价格低廉等优势已经逐步成为研究学者眼中具有潜力的负极材料之一。 碳纳米管具有优良的力学性能和导电性，将其加入电极材料中能够形成有效的导电网络，从而提高充放电性能与能量密度。多壁纳米碳管(MWCNTs)与碳材料复合，一方面多壁纳米碳管有良好的导电性，有利于电子在复合材料中传递，另一方面可是团聚的多壁纳米碳管“解捆”，使电解液对于复合材料有较好的浸润性，有利于电解液离子的传递。本文的主要的研究内容与结果如下： (1)首先，制备出管状聚吡咯和颗粒状聚吡咯。分别在800℃、850℃、900℃、950℃下碳化，得到无定形碳，对比管状和颗粒状的无定形碳。通过XRD、SEM、TEM表征手段对材料进行表征，并对其电化学性能进行测试，得出900℃最优碳化温度。 (2)利用多壁纳米碳管(MWCNTs)对得到的无定形碳进行改性，分别添加2.5wt%、5wt%、10wt%的MWCNTs，采用超声电磁搅拌将MWCNTs和无定形碳进行混合。研究MWCNTs含量对无定形碳/MWCNTs复合材料性能的影响。得出5wt%的添加量相比另外两种比例在电化学性能上更具优势。 (3)使用多壁纳米碳管(MWCNTs)对无定形碳进行改性，分别添加2.5wt%、5wt%、10wt%的MWCNTs，采用球磨法将MWCNTs和无定形碳进行混合。研究MWCNTs含量对无定形碳/MWCNTs复合材料性能的影响。
[Abstract]:The focus of attention in this century is resource utilization, economic development and environmental protection, and the development of battery technology is closely related to the three. Lithium-ion battery has the advantages of high voltage, high specific capacity, green environmental protection and long cycle life. Since it came out in 1991, lithium-ion battery has been three-legged with nickel-chromium battery and nickel-hydrogen battery in the secondary battery market. Cathode material, negative electrode material and electrolyte are the key factors that affect the performance of lithium ion battery. Graphite, a commercial negative electrode material, has the problem of low theoretical capacity, so it is of great significance to develop negative electrode material with excellent performance. Hard carbon has gradually become one of the potential negative electrode materials in the eyes of researchers because of its high specific capacity and low price. Carbon nanotube (CNT) has excellent mechanical properties and conductivity. Adding CNT into the electrode material can form an effective conductive network, thus improving the charge and discharge performance and energy density. Multi-wall carbon nanotube (MWCNTs) and carbon material composite, on the one hand, multi-wall carbon nanotube has good conductivity, which is conducive to electron transfer in the composite material, on the other hand, it can be agglomerated multi-wall carbon nanotube "unbundling". The electrolyte has good wetting property for the composite material, which is beneficial to the ion transfer of the electrolyte. The main contents and results of this paper are as follows: (1) firstly, tubular polypyrrole and granular polypyrrole were prepared. Amorphous carbon was obtained by carbonation at 800 鈩，

本文编号：2488459