红磷基锂离子电池负极材料的制备及其性能研究

发布时间：2018-07-28 18:57

【摘要】：近几年来,新一代以电为动力的电动汽车(EV)以及混合型动力汽车(HEV)的开发研究较为火热,这就使得对于锂离子电池的能量密度以及安全性能等方面提出了更高、更严格的要求。因此,新一代锂离子电池的开发,特别是对于电极材料的开发尤为重要。红磷作为锂离子电池的负极材料具有较高的比容量,理论值可达2596mAh/g,但是由于红磷电导率低、导电性差,单独作为电极材料时,相应的电化学性能较差,通常利用红磷与其他材料的复合来作为锂离子电池的电极来研究其电化学性能。本文利用球磨法分别制备了三个比例的红磷与碳化钨(P/WC)、红磷与花生壳生物碳(P/PS)复合材料,并对其结构进行XRD,SEM以及Raman测试表征。为了研究复合材料的电化学性能,将这几种物质作为锂离子电池的负极材料,分别进行了循环伏安测试(CV)、交流阻抗测试(EIS)和长时间充放电循环测试。将测试结果分析对比,P/WC复合材料样品在7:3的比例下稳定性较好,但比容量较低,在0.2A/g的电流密度下充放循环40周后的比容量为258.43mAh/g;而P/PS样品随着复合材料中PS含量的增加,循环稳定性与充放比容量均有增加,3:7比例样品在0.2A/g电流密度下充放循环100周比容量为774.4mAh/g。为了进一步提高复合材料的比容量与循环稳定性,将比例为7:3的红磷与碳化钨(P/WC)、红磷与花生壳生物碳(P/PS)再与石墨(G)进行球磨复合,并进行电化学测试。将测试结果对比分析,复合材料中由于石墨的引入,不仅能够改善负极活性物质材料的循环稳定性,而且复合材料的比容量也有一定的提高。但石墨对于复合材料的比容量提高有限,进一步增加复合材料中石墨的含量,锂离子电池负极活性物质材料的比容量没有明显增加。
[Abstract]:In recent years, the development and research of new generation electric vehicle (EV) and hybrid electric vehicle (HEV) are hot, which makes the energy density and safety performance of lithium-ion battery put forward higher and stricter requirements. Therefore, the development of a new generation of lithium ion batteries, especially for the development of electrode materials is particularly important. Red phosphorus as a cathode material for lithium ion batteries has a high specific capacity, and the theoretical value can reach 2596 mAh/ g. However, due to the low conductivity and poor conductivity of red phosphorus, the corresponding electrochemical performance is poor when it is used as electrode material alone. The composite of red phosphorus and other materials is usually used as the electrode of lithium ion battery to study its electrochemical performance. In this paper, three proportions of red phosphorus and tungsten carbide (P/WC), red phosphorus and peanut shell biological carbon (P/PS) composites were prepared by ball milling method. In order to study the electrochemical properties of the composite, these materials were used as anode materials for lithium ion batteries. The cyclic voltammetry (CV) (CV), impedance measurement (CV),) and long time charge / discharge cycle (EIS) tests were carried out respectively. Compared with the test results, the samples of P- / WC composites were stable at 7:3, but their specific capacity was lower. The specific capacity of P- / WC composites was 258.43 mAh-g after 40 weeks of charge and release cycle at the current density of 0.2A/g, while the P/PS sample increased with the increase of PS content in the composites. The cycle stability and the charge / discharge capacity of the sample were increased by 3: 7 at 0.2A/g current density. The specific capacity of the 100 week cycle was 774.4 mg 路h / g. In order to further improve the specific capacity and cyclic stability of the composites, red phosphorus and tungsten carbide (P/WC) at 7:3, red phosphorus and peanut shell biological carbon (P/PS) were milled with graphite (G), and electrochemical tests were carried out. By comparing the test results, it is found that the introduction of graphite can not only improve the cyclic stability of the negative active material, but also improve the specific capacity of the composite. However, the specific capacity of graphite to the composite is limited, and the content of graphite in the composite is further increased, and the specific capacity of the anode active material of lithium ion battery is not obviously increased.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM912;TB33

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