锂离子电池负极材料包覆型天然石墨的研究  

Natural graphite- based anode active material coated with iron hydroxide for lithium ion battery

作　　者：李建军[1] 万春荣[1] 姜长印[1] 何向明[1] 何培炯[1] 

机构地区：[1]清华大学核能技术设计研究院,北京100084

出　　处：《清华大学学报（自然科学版）》2001年第6期67-70,共4页Journal of Tsinghua University(Science and Technology)

摘　　要：合成并研究了一种包覆一层氢氧化铁的天然石墨材料 ,它可作为一种新型锂离子电池负极材料。对其电化学性能测试表明 ,当所用电解质为 1m ol/L L i PF6 (EC与 DEC的体积比为 3:7)以 0 .2 5 5 m A.cm- 2充放电时 ,其可逆比容量可超过 35 0 m Ah.g- 1 ,并且具有较好的循环性能。对这种材料进行了 X光衍射分析 (XRD) ,扫描电镜测量 (SEM) ,差重 -热重分析 (DTA- TGA)。从材料的结构、充放电特性和可逆性等方面 ,对锂在该包覆型碳材料中的嵌入机理进行了初步探讨。对该材料的结构分析表明所包覆的氢氧化铁分布较为均匀 ,特别是在天然石墨的端面上包覆的氢氧化铁及其在第一次充放电期间与锂反应生成的固体电解质界面 (SEI)膜 ,能够固定石墨片 ,防止其发生滑移和剥落 。The preparation of a novel natural graphite based anode material coated with iron hydroxide has been studied. The sample was analyzed using X ray diffractometer (XRD), scanning electron microscope (SEM) and differential thermal analysis, thermogravimetric analysis (DTA TGA), and its charge/discharge behaviors were measured. The mechanism of lithium intercalation into the material was anslyzed in terms of its structure, charge/discharge performance and Li + intercalation/ deintercalation reversibility. The results show that the iron hydroxide is uniformily distributed and that the iron hydroxide at the edge of the graphite reacted with Li + during the first discharge process to form a SEI film. The coating and the SEI film fix the graphene to prevent its slippage and exfoliation. This composite anode material has high capacity, excellent lithium intercalation reversibility and high the first charge/discharge cycle efficiency. Its reversible specific capacity is over 350 mA·h/g at 0.225mA/cm 2 charge/discharge current in 1mol/L LiPF 6 (volume ratio of EC and DEC is 3∶7).

关 键 词：锂离子电池 天然石墨 包覆 氢氧化铁 负极材料 固体电解质界面膜 

分 类 号：TM912.9[电气工程—电力电子与电力传动]