Modifying Sn/S Composites on Graphite Anode for Lithium IonBattery

• Main Authors: Tai-ying Hung, 洪苔瑛
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/20317618659828886132

碩士 === 國立臺南大學 === 材料科學系碩士班 === 97 === ABSTRACT Recently, the developments of the high capacity anode materials for lithium ion battery are focused on the metal (such as Sn, Sb). However, most composite oxides and alloy anode materials exhibit rather large capacity loss at the first charge/discharge cycle, as well as capacity fading. Using an electroless plating technique in this study, tin composites modified on graphite (Sn-graphite) has been developed as an alternative anode material for Li-ion battery; this is a cheap and easy way to modify submicro Sn-composite particles on graphite powder surface. The best condition of electroless plating method is found at high concentration Sn4+ (2 mol dm-3) and short plating time (30 sec). Moreover, we use Na2S2O4 as reductant instead of (NH2)2CS to perform the electroless plating. By changing its concentrations and temperatures, and using ehanol to remove extra sulfides from the carbon surface, we found that this would effectively adsorb larger quantity of Sn-composite particles, but smaller in size, on the graphite, and the modified particles would even increase the capacity and cycle life. The morphology of the Sn-modified graphite surface was examined by scanning electron microscope (SEM). Energy dispersive spectroscopy (EDS) and X-ray differaction (XRD) analyses show that the particles are Sn, SnO, and SnS. The electrochemical properties of the Sn-modified graphite were investigated by CV. Finally the Sn-modified graphite anodes were assembled into coin cells which were then tested for their rate capabilities and cycle lifes. The results show that the Sn-modified graphite can enhance the capacity and the cyclability.