Structure Effect of Si-based Powder on Cycle Performance of Lithium Ion Battery D.T. Shieh a , M.H. Yang a , Z.Z. Guo a , P.S. Hsieh a , S. Tsao a , M.W. Lin a , W. R. Liu b , and N.L. Wu b a Material and Chemical Research Laboratories, Industrial Technology Research Institute, Taiwan b Department of Chemical Engineering, National Taiwan University In this study, an inactive material (Ni) is introduced into Si for buffering the volume change causing by the lithium insertion and de-insertion. A porous structure is designed for further reducing of the volume change. The surface-porous structure SiNi powder is prepared by gas atomization method and wet-etching in an acidic solution, which shows positive effects on cycle performance, high capacity and the efficiency at the first cycle. Coated a carbon layer onto SiNi powders by CVD process can further improve the cycle performance by preventing structure collapse. Introduction Lithium ion batteries have received considerable attention due to the increasing demands for portable electronic devices. In commercial batteries, graphite has been used extensively as anode material due to its excellent cycling performance. However, the theoretical capacity of graphite is limited to 372 mAh g − 1 [1,2]. Upon the requirement of high energy density, it’s not good enough for the next generation batteries. Therefore, alternative materials with high volumetric and mass capacity are required for replacing the carbon as anode materials for lithium ion batteries. Anode materials such as Si or Sn alloys with high specific capacities have been investigated. These materials can form alloy with lithium and have much higher theoretical capacities than graphite. The use of Si is particularly interesting due to its high theoretical capacity of 4200 mAh g − 1 [3,4]. The Si may react reversibly with lithium to form a variety of Si–Li alloys and finally arrive at the Li 4.4 Si alloy. However, Si-based anode materials are unable to maintain their structural integrity during the alloying and de-alloying process with lithium due to the large volume changes of Si. These changes cause significant pulverization of the electrodes and decrease the cycling performance to less than few cycles [5,6]. Several approaches have been of ECS Transactions, 3 (27) 3-13 (2007) 10.1149/1.2793573, copyright The Electrochemical Society 3 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 207.241.231.83 Downloaded on 2018-07-20 to IP