本研究探討Ag含量對鋰離子電池中Si負極材料之充放電性質表現。實驗分為兩個部份，第一部分為薄膜電極，第二部分為粉末電極，包含組織結構分析、電化學測試及充放電機制探討。
第一部分薄膜電極利用射頻磁控濺鍍法製備Si-Ag 薄膜負極材料，不同Ag含量 (S15Ag, S22Ag, S28Ag (at. %))當作緩衝物添加入Si基地以改善Si 在充放電循環過程中劇烈的體積變化進而提升循環的穩定性。實驗重點探討Si-Ag薄膜負極材料在室溫、高溫 (55℃) 與熱處理後的充放電性能與電化學特性之關係。實驗結果顯示，當Ag添加量持續增加時，不論在室溫、高溫(55℃)都顯示電容含量有下降趨勢。與室溫相較，電容含量在高溫下明顯上升，而S15Ag 皆在室溫或高溫(55℃)具有最佳放電電容量與庫倫效率。除此之外，S15Ag薄膜電極在真空熱處理350℃一小時後，Cu箔上Cu原子熱擴散至Si-Ag鍍層形成Cu15Si4，其室溫下充放電特性具有提升之效應。
從薄膜電極分析中以Ag添加量最少者(S15Ag)之組成具有最佳的電化學性質表現，後續粉末電極則朝低Ag添加量(15at.%以下)為目的，因此有三種粉末組成設計：P0.5Ag、P3Ag及P15Ag (at.%)。實驗發現粉末電極中適當的Ag添加量有效降低阻抗值；多量的Ag使得電子僅經過Ag顆粒而產生更多較低電容含量之Li-Ag化合物。基於Ag含量與SEI層的雙重影響，並藉由室溫與高溫(55℃)下EIS阻抗分析結果確認，P0.5Ag與P3Ag (at.%)充放電特性由SEI膜(Rsei)所主導。

In this study, Ag was added into Si matrix as the compound film （S15Ag, S22Ag, S28Ag）by RF magnetron sputtering and prevented the volume expansions during the charge-discharge cycling. The electrochemical properties and structural characteristics of Si-Ag films at different ambient temperature (RT/55℃) and the electrodes annealed at 350℃and 450℃ for 1 hour were investigated. As the results, whether at RT or 55℃, the higher amount of Ag increased in Si matrix, decreased discharge capacity. Furthermore, at 55℃, the capacity increased in terms of higher lithium ion diffusion rate. S15Ag electrode had the highest discharge capacity and coulomb efficiency. After the annealing at 350℃, S15Ag electrode had better electrochemical performance.The EIS analysis of powder electrodes at high temperature (55℃) was affected from the two impacts: Ag content and SEI layer. Finally, P0.5Ag and P3Ag specimens were controlled by the SEI film resistance (R sei) and lithium ion diffusion to improve charge-discharge behavior.

[1] M.S. Whittingham, "Electrical energy storage and intercalation chemistry", Science, Vol.192 (4244), pp.1126-1127, 1976.
[2] 黃可龍，劉素琴，王兆翔， ｢鋰離子電池原理與技術｣，五南圖書，臺北市，第12頁，2010。
[3] 黃可龍，劉素琴，王兆翔， ｢鋰離子電池原理與技術｣，五南圖書，臺北市，第244頁，2010。
[4] L.B. Chen, J.Y. Xie, H.C. Yu, T.H. Wang, "Si–Al thin film anode material with superior cycle performance and rate capability for lithium ion batteries", Electrochimica Acta, Vol.53 (28), pp.8149-8153, 2008.
[5] M.D. Fleischauer, M.N. Obrovac, J.R. Dahn, "Al–Si thin-film negative electrodes for Li-ion batteries", Journal of The Electrochemical Society, Vol.155 (11), pp.A851, 2008.
[6] Y.T. Shih, C.H. Wu, F.-Y. Hung, T.S. Lui, L.H. Chen, "A study at room temperature and 55°C on the charge–discharge characteristics of Si(100−x)Alx thin film anode for Li-ion batteries", Surface and Coatings Technology, Vol.215, pp.79-84, 2013.
[7] H.J. Ahn, Y.S. Kim, W.B. Kim, Y.E. Sung, T.Y. Seong, "Formation and characterization of Cu–Si nanocomposite electrodes for rechargeable Li batteries", Journal of Power Sources, Vol.163 (1), pp.211-214, 2006.
[8] Z. Wen, F. Tian, "Cu-doped silicon film as anode for lithium ion batteries prepared by ion-beam sputtering", International Journal of Electrochemical Science, Vol.8 (8) 2013.
[9] J.W. Kim, J.H. Ryu, K.T. Lee, S.M. Oh, "Improvement of silicon powder negative electrodes by copper electroless deposition for lithium secondary batteries", Journal of Power Sources, Vol.147 (1-2), pp.227-233, 2005.
[10] S.M. Hwang, H.Y. Lee, S.W. Jang, S.M. Lee, S.J. Lee, H.K. Baik, J.Y. Lee, "Lithium insertion in SiAg powders produced by mechanical alloying", Electrochemical and Solid-State Letters, Vol.4 (7), pp.A97, 2001.
[11] Z. Wen, X. Yang, S. Huang, "Composite anode materials for Li-ion batteries", Journal of Power Sources, Vol.174 (2), pp.1041-1045, 2007.
[12] Y. Yu, L. Gu, C. Zhu, S. Tsukimoto, P.A. van Aken, J. Maier, "Reversible storage of lithium in silver-coated three-dimensional macroporous silicon", Adv Mater, Vol.22 (20), pp.2247-2250, 2010.
[13] X. Wu, Z. Wang, L. Chen, X. Huang, "Ag-enhanced SEI formation on Si particles for lithium batteries", Electrochemistry Communications, Vol.5 (11), pp.935-939, 2003.
[14] T.D. Hatchard, J.R. Dahn, "Electrochemical reaction of the SiAg binary system with Li", Journal of The Electrochemical Society, Vol.152 (7), pp.A1445, 2005.
[15] W.J. Zhang, "A review of the electrochemical performance of alloy anodes for lithium-ion batteries", Journal of Power Sources, Vol.196 (1), pp.13-24, 2011.
[16] 蕭彤宣，｢銀添加對鋰離子二次電池鎂合金負極材料充放電特性與界面分析之研究｣，國立成功大學材料及工程學系碩士論文，2012。
[17] M. Yoshio, R.J. Brodd, A. Kozawa， "Lithium-Ion Batteries"，Springer，2009.
[18] S. Megahed, B. Scrosati, "Lithium-ion rechargeable batteries", Journal of Power Sources, Vol.51 (1–2), pp.79-104, 1994.
[19] 林志豪，｢鋁、鎳添加物對鋰離子電池陰極材料 - LiMn2O4電性及電化學性質之影響｣，國立成功大學材料及工程學系碩士論文，2003。
[20] W.R. Liu, Z.Z. Guo, W.S. Young, D.T. Shieh, H.C. Wu, M.H. Yang, N.L. Wu, "Effect of electrode structure on performance of Si anode in Li-ion batteries: Si particle size and conductive additive", Journal of Power Sources, Vol.140 (1), pp.139-144, 2005.
[21] M. Winter, J.O. Besenhard, M.E. Spahr, P. Novák, "Insertion electrode materials for rechargeable lithium batteries", Advanced Materials, Vol.10 (10), pp.725-763, 1998.
[22] D. Larcher, S. Beattie, M. Morcrette, K. Edström, J.C. Jumas, J.M. Tarascon, "Recent findings and prospects in the field of pure metals as negative electrodes for Li-ion batteries", Journal of Materials Chemistry, Vol.17 (36), pp.3759, 2007.
[23] U. Kasavajjula, C. Wang, A.J. Appleby, "Nano- and bulk-silicon-based insertion anodes for lithium-ion secondary cells", Journal of Power Sources, Vol.163 (2), pp.1003-1039, 2007.
[24] S.J. Lee, H.Y. Lee, Y. Park, H.K. Baik, S.M. Lee, "Si (–Zr)/Ag multilayer thin-film anodes for microbatteries", Journal of Power Sources, Vol.119-121, pp.117-120, 2003.
[25] C.M. Park, H. Jung, H.J. Sohn, "Electrochemical behaviors and reaction mechanism of nanosilver with lithium", Electrochemical and Solid-State Letters, Vol.12 (9), pp.A171, 2009.
[26] 蕭人瑄，｢鋰離子二次電池鎂-鎳-碳負極材料微觀組織與充放電特性研究｣，國立成功大學奈米科技暨微系統工程研究所碩士論文
，2011。
[27] L.B. Chen, J.Y. Xie, H.C. Yu, T.H. Wang, "An amorphous Si thin film anode with high capacity and long cycling life for lithium ion batteries", Journal of Applied Electrochemistry, Vol.39 (8), pp.1157-1162, 2009.
[28] T.D. Hatchard, M.N. Obrovac, J.R. Dahn, "A comparison of the reactions of the SiSn, SiAg, and SiZn binary systems with L3i", Journal of The Electrochemical Society, Vol.153 (2), pp.A282, 2006.
[29] A.D.W. Todd, P.P. Ferguson, J.G. Barker, M.D. Fleischauer, J.R. Dahn, "Comparison of mechanically milled and sputter deposited tin–cobalt–carbon alloys using small angle neutron scattering", Journal of The Electrochemical Society, Vol.156 (12), pp.A1034, 2009.
[30] L.J. Ning, Y.P. Wu, S.B. Fang, E. Rahm, R. Holze, "Materials prepared for lithium ion batteries by mechanochemical methods", Journal of Power Sources, Vol.133 (2), pp.229-242, 2004.
[31] C.H. Doh, H.M. Shin, D.H. Kim, Y.D. Jeong, S.I. Moon, B.S. Jin, H.S. Kim, K.W. Kim, D.H. Oh, A. Veluchamy, "A new composite anode, Fe–Cu–Si/C for lithium ion battery", Journal of Alloys and Compounds, Vol.461 (1-2), pp.321-325, 2008.
[32] B.C. Kim, H. Uono, T. Satou, T. Fuse, T. Ishihara, M. Ue, M. Senna, "Cyclic properties of Si-Cu/carbon nanocomposite anodes for Li-ion secondary batteries", Journal of The Electrochemical Society, Vol.152 (3), pp.A523, 2005.
[33] C. Joyce, L. Trahey, S.A. Bauer, F. Dogan, J.T. Vaughey, "Metallic copper binders for lithium-ion battery silicon electrodes", Journal of The Electrochemical Society, Vol.159 (6), pp.A909, 2012.
[34] F.M. Smits, "Measurement of sheet resisitivities with the four-point probe", Bell System Technical Journal, Vol.37 (3), pp.711-718, 1958.
[35] X. Yang, Z. Wen, X. Xu, Z. Gu, S. Huang, "Study on the Li+ insertion/extraction for silicon nanosized silver composite electrode", Electrochemical and Solid-State Letters, Vol.10 (3), pp.A52, 2007.
[36] G. Taillades, J. Sarradin, "Silver: high performance anode for thin film lithium ion batteries", Journal of Power Sources, Vol.125 (2), pp.199-205, 2004.
[37] L.F. Cui, L. Hu, J.W. Choi, Y. Cui, "Light-Weight Free-Standing Carbon Nanotube-Silicon Films for Anodes of Lithium Ion Batteries", ACS Nano, Vol.4 (7), pp.3671-3678, 2010.
[38] H. Okamoto, "Cu-Si (copper-silicon)", Journal of Phase Equilibria and Diffusion, Vol.33 (5), pp.415-416, 2012.
[39] A.V. Panin, A.R. Shugurov, I.V. Ivonin, Y.V. Shesterikov, "The role of stress distribution at the film/barrier interface in formation of copper silicides", Semiconductors, Vol.44 (1), pp.116-122, 2010.
[40] A. Netz, R.A. Huggins, W. Weppner, "Investigations of a number of alternative negative electrode materials for use in lithium cells", Ionics, Vol.7 (4-6), pp.433-439, 2001.
[41] H.J. Yang, H. M.Lee, J. Y.Kim, J. H.Lee, J. G.Lee, B. S.Cho, C. O.Jeong, K. H.Chung, C. M.Lee, H. N.Hong, "Mechanism for silicide formation in Ag(Cu)/Si and Ag(Co)/Si upon annealing", Vol.45 (5), pp.5, 2004.
[42] Y.M. Kang, M.S. Park, J.Y. Lee, H.K. Liu, "Si–Cu/carbon composites with a core–shell structure for Li-ion secondary battery", Carbon, Vol.45 (10), pp.1928-1933, 2007.
[43] 吳昭漢，｢射頻磁控濺鍍Cu6Sn5電極之充放電特性研究｣，國立成功大學材料及工程學系碩士論文，2006。
[44] "ASM ready reference", Cverna, Fran A. S. M. International Materials Properties Database Committee, Materials Park, Ohio, 2002.
[45] D.J. Fisher, "Diffusion in silicon : 10 years of research", Scitec Publications, Zuerich-Uetikon, Switzerland, 1998.
[46] J.P. Maranchi, A.F. Hepp, A.G. Evans, N.T. Nuhfer, P.N. Kumta, "Interfacial properties of the a-Si∕Cu:active–inactive thin-film anode system for lithium-ion batteries", Journal of The Electrochemical Society, Vol.153 (6), pp.A1246, 2006.
[47] 黃可龍，劉素琴，王兆翔， ｢鋰離子電池原理與技術｣，五南圖書，臺北市，6-1-5節，2010。
[48] M.D. Levi, D. Aurbach, "Simultaneous Measurements and Modeling of the Electrochemical Impedance and the Cyclic Voltammetric Characteristics of Graphite Electrodes Doped with Lithium", The Journal of Physical Chemistry B, Vol.101 (23), pp.4630-4640, 1997.
[49] P. Zuo, G. Yin, J. Zhao, Y. Ma, X. Cheng, P. Shi, T. Takamura, "Electrochemical reaction of the SiMn/C composite for anode in lithium ion batteries", Electrochimica Acta, Vol.52 (4), pp.1527-1531, 2006.
[50] T. Zhang, H.P. Zhang, L.C. Yang, B. Wang, Y.P. Wu, T. Takamura, "The structural evolution and lithiation behavior of vacuum-deposited Si film with high reversible capacity", Electrochimica Acta, Vol.53 (18), pp.5660-5664, 2008.