隨著科技快速進步，使得全球對環境與能源日益重視，依賴程度也與日俱增；然而我們所生活的社會正面臨著污染、化石燃料不足、全球暖化等環境與能源危機。為了克服這些問題，迫切需要清潔和可再生能源材料及其裝置。超級電容器不僅擁有優異的功率密度與儲電能力，其亦能提供高速充放電速率及長的循環壽命，且操作安全、具環境友好性，其中微型超級電容器由於可進一步與MEMS和CMOS集成，近年來引起了廣泛的研究興趣。
本研究以濺鍍之MoOx薄膜為活性物質製備指叉式微型固態超級電容器，探討具有不同指叉結構組態(指叉總數、間隙、寬度及長度)的平面微型超級電容器，其幾何構型對電化學性質的影響。此外，本研究引入了基於MoOx/Ag多層薄膜結構之指叉式微型固態超級電容器的新概念。電化學交流阻抗分析證實了由於銀薄膜的摻入，MoOx金屬氧化物之低導電率的缺陷得到有效的改善，使得其體積比電容與能量和功率密度遠高於基於MoOx單層薄膜結構的指叉式微型固態超級電容器，且其體積比電容隨著銀摻入的量增而逐漸增加；但加入過量的銀，比電容在連續充放電後的保持率並不會隨此增加，每層銀厚度為1.5 nm的MoOx/Ag多層薄膜結構經過10000次之大數量的循環次數之後，表現出最優異的循環穩定性和最高的體積比電容。
活性材料的高導電性對基於金屬氧化物的擬電容實現高的比電容以及功率和能量密度至關重要。本研究基於單層MoOx與多層MoOx/Ag薄膜結構之指叉式微型固態超級電容器皆展現相當優異的電化學性能，其結果表明所使用之方法和設計對微型儲能系統的應用表現出巨大的前景。

With the scientific and technological advancements, the society which we live is facing the energy and environmental related problems such as pollution, deficiency of fossil fuels, and global warming. In order to resolve these issues, green-energy and renewable materials as well as their devices are demanded. Supercapacitors (SCs) exhibit high specific capacitance and power density, fast charge-discharge rate, and long cycle life. In addition, they are safe in operation and environmental friendly. Recently, micro-supercapacitors (MSCs) have attracted much interests since they can be further integrated into MEMS and CMOS.
In this work, we introduce planar interdigitated electrode structure based on MoOx thin film electrode materials, which can be further fabricated to on-chip and all-solid-state MSC. This study investigated the influence of the geometric configuration of planar interdigitated MSCs with different interdigitated patterns (varying the interspace, width, length and number of interdigitated fingers) on their electrochemical properties. Furthermore, we introduce a new concept to fabricate MSC based on MoOx/Ag multilayers, with which the volumetric capacitance is much higher than that of the bare MoOx-based MSC. MoOx/Ag multilayer MSC also demonstrates higher energy density and power density. Electrochemical impedance spectroscopy (EIS) confirmed that the electrical conductivity of MoOx was significantly improved due to the incorporation of silver. The corresponding volumetric capacitance increases as the the silver thickness increases. But with the excess silver, the capacitance retention rate was found to be degraded. MoOx/Ag multilayers MSC with a thickness of 1.5 nm for each Ag layer exhibits most excellent cycle stability and highest volumetric capacitance after a large cycling number of 10000 times.
This work indicates that high electronic conductivity of the electrode material is crucial to achieving high specific capacity as well as power and energy density for pseudocapacitors. These excellent electrochemical performance of results suggest that our method and design show great promise for applications in integrated energy storage for all solid-state microsystems technologies.

1. M. Jayalashmi and K. Balasubramanian, “Simple capacitors to supercapacitors - an overview,” Int. J. Electrochem. Sci. 3, 1196-1217 (2008).
2. D. P. Dubal, P. Gomez-Romero, B. R. Sankapal and R. Holze, “Nickel Cobaltite as an Emerging Material for Supercapacitors: An Overview,” Nano Energy 11, 377-399(2015).
3. P. Simon and Y. Gogotsi, “Materials for electrochemical capacitors,” Nat. Mater. 7, 845-854(2008).
4. A. González, E. Goikolea, J. A. Barrena and R. Mysyk, “Review on supercapacitors: technologies and materials, ” Renew Sustain Energy Rev. 58, 1189-1206(2016).
5. Z. Yang, J. Zhang, M. C. W. Kintner-Meyer, X. Lu, D. Choi, J. P. Lemmon and J. Liu, “Electrochemical Energy Storage for Green Grid,” Chem. Rev. 111, 3577-3613(2011).
6. Y. Wang, J. Guo, T. Wang, J. Shao, D. Wang and Y.-W. Yang, “Mesoporous Transition Metal Oxides for Supercapacitors,” Nanomaterials 5, 1667-1689(2015).
7. W.-C. Hung, C.-L. Chang and Y.-P. Wang, “石墨烯於超級電容之應用研究,” 新新季刊 第四十二卷第一期, 35-43(2014).
8. R. F. Service, “New ‘supercapacitor’ promises to pack more electrical punch,” Science 313, 902-905(2006).
9. A. K. Shukla, S. Sampath and K. Vijayamohanan, “Electrochemical supercapacitors: Energy storage beyond batteries,” Curr. Sci. 79, 1656-1661(2000).
10. C. D. Lokhande, D. P. Dubal and O. S. Joo, ” Metal oxide thin film based supercapacitors,” Curr. Appl. Phys. 11, 255-270(2011).
11. A. G. Pandolfo and A. F. Hollenkamp, “Carbon properties and their role in supercapacitors,” J. Power Sources 157, 11-27(2006).
12. M. Vangari, T. Pryor and L. Jiang, “Supercapacitors: Review of Materials and Fabrication Methods,” J. Energy Eng. 139, 72-79(2013).
13. R. Kötz and M. Carlen, “Principles and applications of electrochemical capacitors,” Electrochim. Acta 45, 2483-2498(2000).
14. G. Wang, L. Zhang and J. Zhang, “A Review of Electrode Materials for Electrochemical Supercapacitors,” Chem. Soc. Rev. 41, 797-828(2012).
15. L. L. Zhang and X. S. Zhao, “Carbon-based Materials as Supercapacitor Electrodes,” Chem. Soc. Rev. 38, 2520-2531(2009).
16. M. S. Kolathodi, M. Palei and T. S. Natarajan, “Electrospun NiO nanofibers as cathode materials for high performance asymmetric supercapacitors,” J. Mater. Chem. A 3, 7513-7522(2015).
17. J. Q. Xiao, Q. Lu, and J. G. Chen, “Nanostructured Electrodes for High-performance Pseudocapacitors,” Angew. Chem. Int. Ed. 52, 1882-1889(2013).
18. V. Augustyn, P. Simon and B. Dunn, “Pseudocapacitive Oxide Materials for High-rate Electrochemical Energy Storage,” Energy Environ. Sci. 7, 1597-1614(2014).
19. H. Zhao, W. Han, W. Lan, J. Zhou, Z. Zhang, W. Fu and E. Xie, “Bubble Carbon-nanofibers Decorated with MnO2 Nanosheets as High-Performance Supercapacitor Electrode,” Electrochim. Acta 222, 1931-1939(2016).
20. H. Wang, H. S. Casalongue, Y. Liang and H. Dai, “Ni(OH)2 nanoplates grown on graphene as advanced electrochemical pseudocapacitor materials,” J. Am. Chem. Soc. 132, 7472-7477(2010).
21. S. C. Lee, U. M. Patil, S. J. Kim, S. Ahn, S.-W. Kang and S. C. Jun, “All-solid-state flexible asymmetric micro supercapacitors based on cobalt hydroxide and reduced graphene oxide electrodes,” RSC Adv. 6, 43844-43854(2016).
22. C. W. Shen, X. H. Wang, S. W. Li, J. G. Wang, W. F. Zhang and F. Y. Kang, “A high-energy-density micro supercapacitor of asymmetric MnO2-carbon configuration by using micro-fabrication technologies,” J. Power Sources 234, 302-309(2013).
23. Y. Zhang, H. Feng, X. Wu, L. Wang, A. Zhang, T. Xia, H. Dong, X. Li and L. Zhang, “Progress of electrochemical capacitor electrode materials: A review,” Int. J. Hydrogen Energy 34, 4889-4899(2009).
24. S.-M. Chen, R. Ramachandran, V. Mani and R. Saraswathi, “Recent Advancements in Electrode Materials for the High-performance Electrochemical Supercapacitors: A Review,” Int. J. Electrochem. Sci. 9, 4072-4085(2014).
25. T. Zhai, X. Lu, F. Wang, H. Xia and Y. Tong, “MnO2 nanomaterials for flexible supercapacitors: performance enhancement via intrinsic and extrinsic modification,” Nanoscale Horiz. 1, 109-124(2016).
26. G. Salitra, A. Soffer, L. Eliad, Y. Cohen and D. Aurbach, “Carbon Electrodes for Double‐Layer Capacitors I. Relations Between Ion and Pore Dimensions,” J. Electrochem. Soc. 147, 2486-2493(2000).
27. O. Barbieri, M. Hahn, A. Herzog and R. Kotz, “Capacitance limits of high surface area activated carbons for double layer capacitors,” Carbon 43, 1303-1310(2005).
28. D. Qu and H. Shi, “Studies of activated carbons used in double-layer capacitors,” J. Power Sources 74, 99-107(1998).
29. M. Endo, T. Maeda, T. Takeda, Y. J. Kim, K. Koshiba, H. Hara and M. S. Dresselhaus, “Capacitance and Pore-Size Distribution in Aqueous and Nonaqueous Electrolytes Using Various Activated Carbon Electrodes,” J. Electrochem. Soc. 148, A910-A914(2001).
30. J. N. Barisci, G. G. Wallace and R. H. Baughman, “Electrochemical Characterization of Single-Walled Carbon Nanotube Electrodes,” J. Electrochem. Soc. 147, 4580-4583(2000).
31. S. Shiraishi, H. Kurihara, K. Okabe, D. Hulicova and A. Oya, “Electric double layer capacitance of highly pure single-walled carbon nanotubes (HiPcoTM BuckytubesTM) in propylene carbonate electrolytes,” Electrochem. Commun. 4, 593-598(2002).
32. C. Kim, “Electrochemical characterization of electrospun active carbon nanofiber as an electrode in supercapacitor,” J. Power Sources 142, 382-388(2005).
33. Z. Fan, J. Yan, L. Zhi, Q. Zhang, T. Wei, J. Feng, M. Zhang, W. Qian and F. Wei, “A three-dimensional carbon nanotube/graphene sandwich and its application as electrode in supercapacitors,” Adv Mater 22, 3723-3728(2010).
34. Y. Song, J.-L. Xu and X.-X. Liu, “Electrochemical anchoring of dual doping polypyrrole on graphene sheets partially exfoliated from graphite foil for high-performance supercapacitor electrode,” J Power Sources 249, 48-58(2014).
35. C. C. Hu, K. H. Chang, M.C. Lin and Y. T. Wu, “Design and Tailoring of the Nanotublar Arrayed Architecture of Hydrous RuO2 for Next Generation Supercapacitors,” Nano Lett. 6, 2690-2695(2006).
36. S. Devaraj and N. Munichandraiah, “Effect of Crystallographic Structure of MnO2 on its Electrochemical Capacitance Properties,” J. Phys. Chem. C 112, 4406-4417(2008).
37. J. G. Wang, Y. Yang, Z. H. Huang and F. Kang, “Effect of Fe3+ on the Synthesis and Electrochemical Performance of Nanostructured MnO2,” Mater. Chem. Phys. 133, 437-444(2012).
38. L. Lu, H. Xia, J. Feng, H. Wang and M. O. Lai, “MnO2 Nanotube and Nanowire Arrays by Electrochemical Deposition for Supercapacitors,” J. Power Sources 195, 4410-4413 (2010).
39. A. Bahloul, B. Nessark, E. Briot, H. Groult, A. Mauger, K. Zaghib and C. M. Julien, “Polypyrrole-covered MnO2 as Electrode Material for Supercapacitor,” J. Power Sources 240, 267-272(2013).
40. J. Wang, B. Ren, M. Fan, Q. Liu, D. Song and X. Bai, “Hollow NiO Nanofibers Modified by Citric Acid and the Performance as Supercapacitor Electrode,” Electrochim. Acta 92, 197-204(2013).
41. X. Yan, X. Tong, J. Wang, C. Gong, M. Zhang and L. Liang, “Synthesis of Mesoporous NiO Nanoflake Array and its Enhanced Electrochemical Performance for Supercapacitor Applications,” J. Alloys and Compounds 593, 184-189(2014).
42. C. Z. Yuan, L. Yang, L. R. Hou, L. F. Shen, F. Zhang, D. K. Li, X. G. Zhang, “Large-scale Co3O4 nanoparticles growing on nickel sheets via a one-step strategy and their ultra-highly reversible redox reaction toward supercapacitors,” J. Mater. Chem. 21, 18183-18185(2011).
43. K. S. Ryu, K. M. Kim, N.-G. Park, Y. J. Park and S. H. Chang, ” Symmetric redox supercapacitor with conducting polyaniline electrodes,” J. Power Sources 103, 305-309(2002).
44. A. Clémente, S. Panero, E. Spila and B. Scrosati, “Solid-state, polymer-based, redox capacitors,” Solid State Ionics 85, 273-277(1996).
45. A. Laforgue, P. Simon, C. Sarrazin and J.-F. Fauvarque, “Polythiophene-based supercapacitors,” J. Power Sources 80, 142(1999).
46. F. Selampinar, U. Akbulut and L. Toppare, “Conducting polymer composites of polypyrrole and polyimide,” Synth. Met. 84, 185-186(1997).
47. C. Zhong, Y. Deng, W. Hu, J. Qiao, L. Zhang and J. J. Zhang, “A review of electrolyte materials and compositions for electrochemical supercapacitors,” Chem. Soc. Rev. 44, 7484-7539(2015).
48. H. Gao and K. Lian, “Proton-conducting polymer electrolytes and their applications in solid supercapacitors: a review,” RSC Adv. 4, 33091-33113(2014).
49. 胡啟章, “電化學原理與方法(二版),” 五南圖書出版, (2002).
50. Francois Beguin(著), Elzbieta Frackowiak(著), 張治安(譯), “超級電容器：材料、系統及應用,” 機械工業出版, (2014).
51. D. S. Yu, K. Goh, H. Wang, L. Wei, W. C. Jiang, Q. Zhang, L. M. Dai and Y. Chen, “Scalable synthesis of hierarchically structured carbon nanotube-graphene fibres for capacitive energy storage,” Nat. Nanotech. 9, 555-562(2014).
52. W. Zaidi, A. Boisset, J. Jacquemin, L. Timperman and M. Anouti, “Deep Eutectic Solvents Based on N-Methylacetamide and a Lithium Salt as Electrolytes at Elevated Temperature for Activated Carbon-Based Supercapacitors,” J. Phys. Chem. C 118, 4033-4042(2014).
53. X.-M. Liu, R. Zhang, L. Zhan, D.-H. Long, W.-M. Qiao, J.-H. Yang and L.-C. Ling, “Impedance of carbon aerogel/activated carbon composites as electrodes of electrochemical capacitors in aprotic electrolyte,” New Carbon Mater 22, 153-1588(2007).
54. D. Pech, M. Brunet, T. M. Dinh, K. Armstrong, J. Gaudet and D. Guay, “Influence of the configuration in planar interdigitated electrochemical micro-capacitors,” J. Power Sources 230 , 230-235(2013).
55. B. Huang, X.-Z. Sun, X. Zhang, D.-C. Zhang and Y.-W. Ma, “活性炭基軟包裝超級電容器用有機電解液,” Acta Phys.-Chim. Sin. 29, 1998-2004(2013).
56. M. Beidaghi and Y. Gogots, “Capacitive energy storage in micro-scale devices: recent advances in design and fabrication of microsupercapacitors,” Energy Environ. Sci. 7, 867-884(2014).
57. C. W. Shen, X. H. Wang, W. F. Zhang and F. Y. Kang, “A high-performance three-dimensional micro supercapacitor based on self-supporting composite materials,” J. Power Sources 196, 10465-10471 (2011).
58. D. Pech, M. Brunet, H. Durou, P. Huang, V. Mochalin, Y. Gogotsi, P.-L. Taberna and P. Simon, “Ultrahigh-power micrometre-sized supercapacitors based on onion-like carbon,” Nature Nanotech. 5, 651-654 (2010).
59. Z. Zeng, X. Long, H. Zhou, E. Guo, X. Wang and Z. Hu, “On-chip interdigitated supercapacitor based on nano-porous gold/manganese oxide nanowires hybrid electrode,” Electrochim. Acta 163, 107-115(2015).
60. M. Beidaghi and C. Wang, “Micro-Supercapacitors Based on Interdigital Electrodes of Reduced Graphene Oxide and Carbon Nanotube Composites with Ultrahigh Power Handling Performance,” Adv. Funct. Mater. 22, 4501-4510(2012).
61. W. Si, C. Yan, Y. Chen, S. Oswald, L. Han and O.G. Schmidt, “On chip, all solid-state and flexible micro-supercapacitors with high performance based on MnOx/Au multilayers,” Energy Environ. Sci. 6, 3218-3223(2013).
62. K. Wang, W. J. Zou, B. Quan, A. F. Yu, H. P. Wu, P. Jiang and Z. X. Wei, “An All-Solid-State Flexible Micro-supercapacitor on a Chip,” Adv. Energy Mater. 1, 1068-1072(2011).
63. E. Eustache, C. Douard, R. Retoux, C. Lethien and T. Brousse, “MnO2 Thin Films on 3D Scaffold: Microsupercapacitor Electrodes Competing with “Bulk” Carbon Electrodes,” Adv. Energy Mater., 1500680(2015).
64. Y. D. Zhang, B. P. Lin, Y. Sun, P. Han, J. C. Wang, X. J. Ding, X. Q. Zhang and H. Yang, “MoO2@Cu@C Composites Prepared by Using Polyoxometalates@Metal-Organic Frameworks as Template for All-Solid-State Flexible Supercapacitor,” Electrochim. Acta, 188, 490-498(2016).
65. X. H. Lu, T. Zhai, X. H. Zhang, Y. Q. Shen, L. Y. Yuan, B. Hu, L. Gong, J. Chen, Y. H. Gao, J. Zhou, Y. X. Tong and Z. L. Wang, “WO3-x@Au@MnO2 Core-Shell Nanowires on Carbon Fabric for High-Performance Flexible Supercapacitors,” Adv. Mater. 24, 938-944(2012).
66. J. Zhou, J. Lian, L. Hou, J. Zhang, H. Gou, M. Xia, Y. Zhao, T. A. Strobel, L. Tao and F. Gao, “Ultrahigh volumetric capacitance and cyclic stability of fluorine and nitrogen co-doped carbon microspheres,” Nat. Commun. 6, 8503(2015).
67. T. Qiu, B. Luo, M. Giersig, E. M. Akinoglu, L. Hao, X. Wang, L. Shi, M. Jin and L. Zhi, “Au@MnO2 Core-Shell Nanomesh Electrodes for Transparent Flexible Supercapacitors,” Small 10, 4136-4141(2014).
68. C. Y. Yang, J. L. Shen, C. Y. Wang, H. J. Fei, H. Bao and G. C. Wang, “All-solid-state asymmetric supercapacitor based on reduced graphene oxide/carbon nanotube and carbon fiber paper/polypyrrole electrodes,” J. Mater. Chem. A 2, 1458-1464(2014).