新型石墨烯基复合膜负极材料的制备及其在锂离子电池中的应用

发布时间：2018-03-12 08:34

本文选题：锂离子电池　切入点：负极材料　出处：《南昌大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,可充电锂离子电池已经广泛应用移动手机、数码相机和其它电子产品,并且在电动汽车或混合动力电动汽车领域表现出了很好的应用前景。但是,由于其较低的理论容量和较大的锂枝晶,石墨作为商业化的锂离子电池负极材料越来越不能满足人们对大型高容量、高功率锂离子电池需求和期待。为了开发新一代高性能锂离子电池,各种负极材料包括新型碳材料(碳管、碳纤维和石墨烯),金属氧化物(Co Ox和Mn Ox)和金属硫化物(Mo S_2和Sn S_2)被广泛研究。很多研究表明,金属氧化物和金属硫化物电极材料尽管具有较大的比容量,显示出优秀的储锂能力,但在实际应用中也存在显著的缺点:比如,低的电导率导致其在高倍率下的放电性能很差;锂离子嵌入脱出过程中巨大的体积变化,导致容量迅速的衰减。本论文研究内容如下:1. 采用嵌锂插层结合液相剥离的方法制备二硫化钼纳米片。剥离的二硫化钼纳米片的结构和形貌采用XRD、XPS、SEM、TEM及AFM方法进行表征。结果表明此种方法制备的二硫化钼纳米片呈单片层和少数片层。2.采用静电喷涂和光波还原技术制备出Mo S_2/RGO复合材料。将该材料应用于锂离子电池负极材料,与Mo S_2相比,Mo S_2/RGO复合材料展现了较好的电化学性能:高的比容量(在0.1 A g~(-1)电流密度下容量为1242.7 m Ah g~(-1));极好的倍率性能(2.0 A g~(-1)电流密度下容量为533.7 m Ah g~(-1)和5.0 A g~(-1)电流密度下容量为361.6 m Ah g~(-1));较好的循环稳定性(0.1 A g~(-1)电流密度下循环100次后容量为533.7 m Ah g~(-1),2.0 A g~(-1)电流密度下循环1000次后容量为361.6 m Ah g~(-1))。3.采用静电纺丝和常压气相沉积法制备出Mn O/CNFs@G纳米纤维膜。将膜直接用作无粘结剂的锂离子电池,展现出极好电化学性能:在电流密度5 A g~(-1)下,1000次循环后可逆容量为490.7 m Ah g~(-1);即使在大电流密度10 A g~(-1)下5000次循环后可逆容量为367.4 m Ah g~(-1)且库伦效率为99.8%。
[Abstract]:In recent years, rechargeable lithium ion batteries have been widely used in mobile phones, digital cameras and other electronic products, and have shown good prospects in the field of electric vehicles or hybrid electric vehicles. Because of its low theoretical capacity and large lithium dendrite, graphite as a commercial anode material for lithium-ion batteries can not meet the needs of large scale and high capacity. In order to develop a new generation of high-performance lithium-ion batteries, a variety of anode materials including new carbon materials (carbon tubes, Carbon fiber and graphene, metal oxides CoOx and mn Ox) and metal sulphides Mo S2 and Sn S2) have been extensively studied. Many studies have shown that metal oxide and metal sulphide electrode materials, despite their large specific capacity, It shows excellent lithium storage ability, but it also has obvious disadvantages in practical application: for example, low conductivity leads to poor discharge performance at high rate, large volume change in the process of intercalation and stripping of lithium ion, The content of this thesis is as follows: 1. Molybdenum disulfide nanocrystals were prepared by intercalation of lithium intercalation and liquid phase stripping. The structure and morphology of the stripped molybdenum disulfide nanocrystals were carried out by means of XRDX, XPS, SEMTEM and AFM methods. The results show that the molybdenum disulfide nanoplates prepared by this method are monolayer and a few layers. 2. The molybdenum disulfide nanocrystals are prepared by electrostatic spraying and photo-wave reduction techniques. The composites are used as anode materials for lithium ion batteries. Compared with MOS _ 2 / R _ (2), the composite shows better electrochemical properties: high specific capacity (1242.7 mAh / g ~ (-1) at current density and 533.7 mAh / g ~ (-1)) and 5.0 A at current density. The capacity at current density is 361.6 mAh / g ~ (-1) and good cyclic stability is 0.1 A / g ~ (-1)) at current density, the capacity of 100 cycles is 533.7 m Ah / g ~ (-1) and the capacity after 1000 cycles is 361.6 mAh / g / g ~ (-1) at the current density of 533.7 m Ah / g / g ~ (-1). Using electrostatic spinning and atmospheric pressure gas, the capacity is 361.6 m / g / g ~ (-1). The mn O / CNFsG nanofiber membrane was prepared by phase deposition. The membrane was used directly as a binder free lithium ion battery. It shows excellent electrochemical properties: the reversible capacity of 1 000 cycles is 490.7 mAh / g ~ (-1) at current density 5 A / g ~ (-1), and the reversible capacity of 5 000 cycles is 367.4 mAh / g ~ (-1) even at high current density (10 A / g ~ (-1)), and the Coulomb efficiency is 99.8 m 路g ~ (-1).
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM912;TB332

【相似文献】