本研究首先透過水熱法合成奈米級二氧化鈦(nano-sized TiO2)，並添加聚氧化乙烯(polyethylene oxide, PEO)進行改質抑制顆粒變大，以提升固態高分子電解質的離子導電度。第二部分則是提升活性材料的電化學性質，例如：鈉離子電池中Na2/3Co2/3Mn1/2O2陰極材料被PEDOT/PSS包覆後其循環穩定性、電容量維持率、變速率下材料的穩定性以及庫倫效率的檢測與分析。
本文將聚氧化乙烯 (polyethylene oxide, PEO)、高氯酸鈉鹽 (NaClO4 salt) 和奈米級二氧化鈦 (nano-sized TiO2) 透過溶液成膜的技術合成之複合物作為固態高分子電解質。此固態高分子電解質為一層透明薄膜且具有導電特性，因此在電池組裝時不須額外添加導電材料於鈉離子電池中。材料鑑定上利用X-ray繞射光譜 (X-ray diffraction, XRD) 與傅立葉轉換紅外線光譜 (Fourier transformed infrared spectra, FTIR)，瞭解材料的結晶性以及PEO與鈉離子間的反應機制，並進一步瞭解PEO中氧原子與鈉之比例(EO:Na)對離子導電度之影響。離子導電度則透過交流阻抗分析儀進行檢測，頻率設定範圍為1 MHz 至 1 Hz，溫度設定為303 至 363 K。結果顯示當 EO:Na 的原子比等於20時，固態高分子電解質的最高離子導電度為1.3510−4 Scm−1，鈉離子溶劑化的程度最高；而當溫度上升至60 oC時，且添加二氧化鈦(3.4 nm, 5 wt%)後的離子導電度可提升至2.6210−4 Scm−1。
本研究接著比較固態高分子電解質與一般液體電解液對於Na2/3Co2/3Mn1/3O2半電池電性的影響。Na2/3Co2/3Mn1/3O2陰極材料透過不同比例的聚(3,4-乙烯二氧基噻吩)-聚(苯乙烯磺酸)((3,4-ethylene dioxythiophene)-poly (styrene sulfonate), PEDOT/PSS)進行表面改質後，由於表面的PEDOT/PSS可以提升電子傳遞速率、抑制阻抗層的生成以及抑制陰極材料中過渡金屬的分解，而使得電池擁有高電容量與穩定性佳的特性。本研究成功以表面改質技術提升鈉離子電池中Na2/3Co2/3Mn1/3O2經過多數循環圈數後的電容量與增加其穩定性。

關鍵字: 固態高分子電解質、奈米複合物、鈉離子電池、導電度、高氯酸鈉、阻抗、PEDOT/PSS、陰極、Na2/3Co2/3Mn1/3O2

The first issue in this research is to increase the ionic conductivity in a solid polymer electrolyte consisting of PEO based and NaClO4 salt by incorporating TiO2 nanoparticles to prepare a nanocomposite electrolyte. The nanosized TiO2 filler was prepared by hydrothemal synthesis, where PEO was added to inhibit the growth of particle size. The second issue is increasing the electrochemical performance like cycling stability, capacity retention, rate capability performance and the efficiency of Na2/3Co2/3Mn1/2O2 cathode material by coating PEDOT/PSS for sodium ion batteries.
A free-standing sodium-ion conducting transparent film comprising a solid polymer electrolyte, based on polyethylene oxide (PEO) complexed with a NaClO4 salt and nano-sized TiO2 was obtained using a solution casting technique. The crystallinity of the solid polymer electrolyte and the interactions between PEO and the Na cations were characterized by X-ray diffraction (XRD) and Fourier Transformed Infrared (FTIR) spectroscopy, these analyses also revealed the degree of solvation of Na+ ion by PEO oxygen atoms (EO:Na). The ionic conductivities of the films were investigated by impedance analysis with the frequency ranging from 1 MHz to 1 Hz within the temperature window 303 – 363 K. A solid polymer electrolyte (atomic ratio of EO:Na = 20) exhibited a maximum ionic conductivity of 1.3510−4 Scm−1, which was improved to 2.6210−4 Scm−1 by the addition of TiO2 (3.4 nm, 5 wt%) at temperature 60 oC. The performance of the Na2/3Co2/3Mn1/3O2 half cell with a polymer electrolyte is compared to that with a liquid electrolyte.
The electrochemical properties of Na2/3Co2/3Mn1/3O2 cathode material, surface-modified using various contents of a conductive polymer, namely (3,4-ethylene dioxythiophene)-poly (styrene sulfonate) (PEDOT/PSS), were investigated. The surface-modified Na2/3Co2/3Mn1/3O2 exhibited a high discharge capacity and a good rate capability, due to enhanced electron transport by surface PEDOT/PSS. The presence of the PEDOT/PSS surface layer suppressed the growth of a resistive layer, while the dissolution of transition metals from the active cathode material was also inhibited. The resulting surface-modified Na2/3Co2/3Mn1/3O2 showed superior a cycling performance and better stability compared to an uncoated electrode when used as a sodium-ion battery cathode.

Keywords: Solid Polymer Electrolyte, Nanocomposite, Sodium-ion battery, Conductivity, NaClO4, impedance, PEDOT/PSS, cathode, Na2/3Co2/3Mn1/3O2

1. Dunn, B., et al., Electrical Energy Storage for the Grid: A Battery of Choices. Science, 2011. 334: p. 928.
2. Yang, Z., et al., Electrochemical Energy Storage for Green Grid. Chemical Reviews, 2011. 111(5): p. 3577-3613.
3. Ibrahim, H., A. Ilinca, and J. Perron, Energy storage systems—Characteristics and comparisons. Renewable and Sustainable Energy Reviews, 2008. 12(5): p. 1221-1250.
4. Chen, H., et al., Progress in electrical energy storage system: A critical review. Progress in Natural Science, 2009. 19(3): p. 291-312.
5. Palomares, V., et al., Na-ion batteries, recent advances and present challenges to become low cost energy storage systems. Energy & Environmental Science, 2012. 5(3): p. 5884-5901.
6. Ellis, B.L. et al.,, Sodium and sodium-ion energy storage batteries. Current Opinion in Solid State and Materials Science, 2012. 16(4): p. 168-177.
7. Kim, S.-W., et al., Electrode Materials for Rechargeable Sodium-Ion Batteries: Potential Alternatives to Current Lithium-Ion Batteries. Advanced Energy Materials, 2012. 2(7): p. 710-721.
8. Slater, M.D., et al., Sodium-Ion Batteries. Advanced Functional Materials, 2013. 23(8): p. 947-958.
9. Palomares, V., et al., Update on Na-based battery materials. A growing research path. Energy & Environmental Science, 2013. 6(8): p. 2312-2337.
10. Chevrier, V.L. et al, Challenges for Na-ion Negative Electrodes. Journal of The Electrochemical Society, 2011. 158(9): p. A1011-A1014.
11. Pan, H., Y.-S. Hu, and L. Chen, Room-temperature stationary sodium-ion batteries for large-scale electric energy storage. Energy & Environmental Science, 2013. 6(8): p. 2338-2360.
12. Komaba, S., et al., Electrochemical Na Insertion and Solid Electrolyte Interphase for Hard-Carbon Electrodes and Application to Na-Ion Batteries. Advanced Functional Materials, 2011. 21(20): p. 3859-3867.
13. Komaba, S., et al., Fluorinated Ethylene Carbonate as Electrolyte Additive for Rechargeable Na Batteries. ACS Applied Materials & Interfaces, 2011. 3(11): p. 4165-4168.
14. Yabuuchi, N., et al., P2-type Nax [Fe1/2Mn1/2] O2 made from earth-abundant elements for rechargeable Na batteries. Nature materials, 2012. 11(6): p. 512-517.
15. Bucher, N., et al., Layered NaxMnO2+z in Sodium Ion Batteries–Influence of Morphology on Cycle Performance. ACS Applied Materials & Interfaces, 2014. 6(11): p. 8059-8065.
16. Armand, M., Polymer solid electrolytes - an overview. Solid State Ionics, 1983. 9–10, Part 2(0): p. 745-754.
17. Shin, J.-H., et al., Ionic liquids to the rescue? Overcoming the ionic conductivity limitations of polymer electrolytes. Electrochemistry Communications, 2003. 5(12): p. 1016-1020.
18. Kishimoto, K., et al., Nanostructured Anisotropic Ion-Conductive Films. Journal of the American Chemical Society, 2003. 125(11): p. 3196-3197.
19. Armand, M., The history of polymer electrolytes. Solid State Ionics, 1994. 69(3–4): p. 309-319.
20. West, K., Solid State Sodium Batteries. Lithium batteries: new materials, developments, and perspectives, 1994. 5: p. 323.
21. Fenton, D., et al., Complexes of alkali metal ions with poly (ethylene oxide). Polymer, 1973. 14(11): p. 589.
22. Cho, B.-K., et al., Mesophase Structure-Mechanical and Ionic Transport Correlations in Extended Amphiphilic Dendrons. Science, 2004. 305(5690): p. 1598-1601.
23. Zhang, C., et al., Alkali metal crystalline polymer electrolytes. Nat Mater, 2009. 8(7): p. 580-584.
24. Smitha, B., et al., Synthesis and characterization of proton conducting polymer membranes for fuel cells. Journal of Membrane Science, 2003. 225(1): p. 63-76.
25. Mauritz, K.A. et al., State of understanding of nafion. Chem Rev, 2004. 104(10): p. 4535-85.
26. Nishimoto, A., et al., High ionic conductivity of new polymer electrolytes based on high molecular weight polyether comb polymers. Electrochimica Acta, 1998. 43(10–11): p. 1177-1184.
27. Appetecchi, G.B., et al., Hot-pressed, solvent-free, nanocomposite, PEO-based electrolyte membranes: II. All solid-state Li/LiFePO4 polymer batteries. Journal of Power Sources, 2003. 124(1): p. 246-253.
28. Lepage, D., et al., A Soft Chemistry Approach to Coating of LiFePO4 with a Conducting Polymer. Angewandte Chemie International Edition, 2011. 50(30): p. 6884-6887.
29. Lee, Y.-S., et al., Effect of an organic additive on the cycling performance and thermal stability of lithium-ion cells assembled with carbon anode and LiNi< sub> 1/3</sub> Co< sub> 1/3</sub> Mn< sub> 1/3</sub> O< sub> 2</sub> cathode. Journal of Power Sources, 2011. 196(16): p. 6997-7001.
30. Yao, Y., et al., Improving the cycling stability of silicon nanowire anodes with conducting polymer coatings. Energy Environ. Sci., 2012. 5(7): p. 7927-7930.
31. Zhou, J. et al., Improving Electrical Conductivity in Polycarbonate Nanocomposites Using Highly Conductive PEDOT/PSS Coated MWCNTs. ACS Applied Materials & Interfaces, 2013. 5(13): p. 6189-6200.
32. Dziewoński, P.M. et al., Towards TiO2-conducting polymer hybrid materials for lithium ion batteries. Electrochimica Acta, 2010. 55(9): p. 3336-3347.
33. Yang, Y., et al., ACS Nano, 2011. 5: p. 9187.
34. Ju, S.H., et al., Improvement of the Cycling Performance of LiNi0.6Co0.2Mn0.2O2 Cathode Active Materials by a Dual-Conductive Polymer Coating. ACS Applied Materials & Interfaces, 2014. 6(4): p. 2546-2552.
35. Liu, X., et al., PEDOT modified LiNi1/3Co1/3Mn1/3O2 with enhanced electrochemical performance for lithium ion batteries. Journal of Power Sources, 2013. 243: p. 374-380.
36. van Schalkwijk, W. et al., Advances in lithium-ion batteries. 2002: Springer Science & Business Media.
37. Tarascon, J.M. et al., Issues and challenges facing rechargeable lithium batteries. Nature, 2001. 414(6861): p. 359-367.
38. Armand, M. et al., Building better batteries. Nature, 2008. 451(7179): p. 652-657.
39. Xu, K., Nonaqueous liquid electrolytes for lithium-based rechargeable batteries. Chemical reviews, 2004. 104(10): p. 4303-4418.
40. Gray, F.M., SOLID POLYMER ELECTROLYTES: FUNDAMENTALS AND TECHNOLOGICAL APPLICATIONS. 1991, London, New York: VCH.
41. Plieth, W., Electrochemistry for materials science. 2008: Elsevier.
42. Doyle, M., et al., Modeling of Galvanostatic Charge and Discharge of the Lithium/Polymer/Insertion Cell. Journal of The Electrochemical Society, 1993. 140(6): p. 1526-1533.
43. Fuller, T.F., et al., Simulation and optimization of the dual lithium ion insertion cell. Journal of the Electrochemical Society, 1994. 141(1): p. 1-10.
44. Doyle, M., et al., The importance of the lithium ion transference number in lithium/polymer cells. Electrochimica Acta, 1994. 39(13): p. 2073-2081.
45. Patel, M., et al., Increasing ionic conductivity of polymer–sodium salt complex by addition of a non-ionic plastic crystal. Solid State Ionics, 2010. 181(17–18): p. 844-848.
46. Mohan, V.M., et al., Structural, electrical and optical properties of pure and NaLaF4 doped PEO polymer electrolyte films. Journal of Polymer Research, 2007. 14(4): p. 283-290.
47. Mohapatra, S., et al., Studies on PEO-based sodium ion conducting composite polymer films. Ionics, 2008. 14(3): p. 255-262.
48. Manuel Stephan, A., et al., Review on composite polymer electrolytes for lithium batteries. Polymer, 2006. 47(16): p. 5952-5964.
49. Song, J., et al., Y. Wang, and C. Wan, Review of gel-type polymer electrolytes for lithium-ion batteries. Journal of Power Sources, 1999. 77(2): p. 183-197.
50. Wieczorek, W., et al., Effect of Salt Concentration on the Conductivity of PEO-Based Composite Polymeric Electrolytes. The Journal of Physical Chemistry B, 1998. 102(44): p. 8725-8731.
51. Bhide, A. et al., Composite polymer electrolyte based on (PEO)6:NaPO3 dispersed with BaTiO3. Polymer International, 2008. 57(3): p. 523-529.
52. Dey, A., et al., Vibrational spectroscopy and ionic conductivity of polyethylene oxide–NaClO4–CuO nanocomposite. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2011. 83(1): p. 384-391.
53. Ito, Y., et al., Ionic conductivity of electrolytes formed from PEO-LiCF3SO3 complex low molecular weight poly(ethylene glycol). Journal of Materials Science, 1987. 22(5): p. 1845-1849.
54. West, K., et al., Layered potassium vanadium oxides as host materials for lithium and sodium insertion. Solid State Ionics, 1990. 40–41, Part 2(0): p. 585-588.
55. Koksbang, R., et al., Lithium and sodium insertion in ternary chromium oxides. Solid State Ionics, 1988. 28–30, Part 1(0): p. 868-872.
56. Stoko̵sa, A., et al., Structure of ionic and electronic defects in cobalt bronze NaxCoO2. Solid State Ionics, 1985. 15(3): p. 211-216.
57. Molenda, J., et al., Transport properties of NaxCoO2−y. Solid State Ionics, 1984. 12(0): p. 473-477.
58. Sequeira, C.A.C., et al., Stability domain of a complexed lithium salt-poly(ethylene oxide) polymer electrolyte. Solid State Ionics, 1984. 13(2): p. 175-179.
59. Molenda, J., Correlation between electronic and electrochemical properties of AxMO2-type electrode materials. Electronic criterion. Solid State Ionics, 1986. 21(4): p. 263-272.
60. Chick, L.A., et al., Glycine-nitrate combustion synthesis of oxide ceramic powders. Materials Letters, 1990. 10(1): p. 6-12.
61. Osada, Y., et al.,, A polymer gel with electrically driven motility. Nature, 1992. 355(6357): p. 242-244.
62. Simone, P.M. et al., Phase behavior and ionic conductivity of concentrated solutions of polystyrene-poly (ethylene oxide) diblock copolymers in an ionic liquid. ACS applied materials & interfaces, 2009. 1(12): p. 2812-2820.
63. Kim, S.Y., et al., Enhanced proton transport in nanostructured polymer electrolyte/ionic liquid membranes under water-free conditions. Nat Commun, 2010. 1: p. 88.
64. Bruce, P.G., et al., Nanomaterials for Rechargeable Lithium Batteries. Angewandte Chemie International Edition, 2008. 47(16): p. 2930-2946.
65. Subramania, A., et al., Preparation of a novel composite micro-porous polymer electrolyte membrane for high performance Li-ion battery. Journal of Membrane Science, 2007. 294(1–2): p. 8-15.
66. Balaya, P., et al., Nano-ionics in the context of lithium batteries. Journal of power sources, 2006. 159(1): p. 171-178.
67. Yang, C.-M., et al., Gel-type polymer electrolytes with different types of ceramic fillers and lithium salts for lithium-ion polymer batteries. Journal of power sources, 2006. 156(2): p. 574-580.
68. Yap, Y.L., et al., Inorganic Filler Sizes Effect on Ionic Conductivity in Polyethylene Oxide (PEO) Composite Polymer Electrolyte. International Journal of Electrochemcal Science, 2013. 8(2): p. 2154-2163.
69. Kumar, D. et al., Ionic liquid based sodium ion conducting gel polymer electrolytes. Solid State Ionics, 2010. 181(8–10): p. 416-423.
70. Traversa, E., et al., Sol-gel processed TiO2-based nano-sized powders for use in thick-film gas sensors for atmospheric pollutant monitoring. Journal of sol-gel science and technology, 2001. 22(1-2): p. 167-179.
71. Chen, X., et al., Titanium dioxide nanomaterials: synthesis, properties, modifications, and applications. Chemical reviews, 2007. 107(7): p. 2891-2959.
72. Leroux, F., et al., Study of the formation of mesoporous titania via a template approach and of subsequent Li insertion. Journal of Materials Chemistry, 2002. 12(11): p. 3245-3253.
73. Litter, M.I. et al., Comparison of the photocatalytic efficiency of TiO 2, iron oxides and mixed Ti (IV) Fe (III) oxides: photodegradation of oligocarboxylic acids. Journal of Photochemistry and Photobiology A: Chemistry, 1994. 84(2): p. 183-193.
74. Palmisano, L., et al., Activity of chromium-ion-doped titania for the dinitrogen photoreduction to ammonia and for the phenol photodegradation. The Journal of Physical Chemistry, 1988. 92(23): p. 6710-6713.
75. Wang, Y., et al., Preparation, characterization and photoelectrochemical behaviors of Fe(III)-doped TiO2 nanoparticles. Journal of Materials Science, 1999. 34(15): p. 3721-3729.
76. Cheng, H., et al., Hydrothermal preparation of uniform nanosize rutile and anatase particles. Chemistry of Materials, 1995. 7(4): p. 663-671.
77. Wang, Y., et al., The photoelectrochemistry of transition metal-ion-doped TiO2 nanocrystalline electrodes and higher solar cell conversion efficiency based on Zn2+-doped TiO2 electrode. Journal of Materials Science, 1999. 34(12): p. 2773-2779.
78. Akhtar, M.K., et al., Vapor synthesis of titania powder by titanium tetrachloride oxidation. AIChE Journal, 1991. 37(10): p. 1561-1570.
79. Li, W., et al., Metallorganic chemical vapor deposition and characterization of TiO 2 nanoparticles. Materials Science and Engineering: B, 2002. 96(3): p. 247-253.
80. Wang, C.-C., et al., Photocatalytic decomposition of halogenated organics over nanocrystalline titania. Nanostructured Materials, 1997. 9(1–8): p. 583-586.
81. Nagelberg, A.S. et al., A thermodynamic study of sodium-intercalated TaS2 and TiS2. Journal of Solid State Chemistry, 1979. 29(3): p. 345-354.
82. Delmas, C., et al., Electrochemical intercalation of sodium in NaxCoO2 bronzes. Solid State Ionics, 1981. 3–4(0): p. 165-169.
83. West, K., et al., Sodium insertion in vanadium oxides. Solid State Ionics, 1988. 28–30, Part 2(0): p. 1128-1131.
84. Ong, S.P., et al., Voltage, stability and diffusion barrier differences between sodium-ion and lithium-ion intercalation materials. Energy & Environmental Science, 2011. 4(9): p. 3680-3688.
85. Berthelot, R., et al., Electrochemical investigation of the P2-NaxCoO2 phase diagram. Nat Mater, 2011. 10(1): p. 74-80.
86. Cao, Y., et al., Reversible sodium ion insertion in single crystalline manganese oxide nanowires with long cycle life. Adv Mater, 2011. 23(28): p. 3155-60.
87. Ma, X., et al., Electrochemical Properties of Monoclinic NaMnO2. Journal of The Electrochemical Society, 2011. 158(12): p. A1307-A1312.
88. Caballero, A., et al., Synthesis and characterization of high-temperature hexagonal P2-Na0.6 MnO2 and its electrochemical behaviour as cathode in sodium cells. Journal of Materials Chemistry, 2002. 12(4): p. 1142-1147.
89. Yabuuchi, N., et al., Crystal structures and electrode performance of alpha-NaFeO 2 for rechargeable sodium batteries. Electrochemistry, 2012. 80(10): p. 716-719.
90. Komaba, S., et al., Study on the Reversible Electrode Reaction of Na1–x Ni0. 5Mn0. 5O2 for a Rechargeable Sodium-Ion Battery. Inorganic chemistry, 2012. 51(11): p. 6211-6220.
91. Sathiya, M., et al., Synthesis, structure, and electrochemical properties of the layered sodium insertion cathode material: NaNi1/3Mn1/3Co1/3O2. Chemistry of Materials, 2012. 24(10): p. 1846-1853.
92. Buchholz, D., et al., Toward Na-ion Batteries Synthesis and Characterization of a Novel High Capacity Na Ion Intercalation Material. Chemistry of Materials, 2013. 25(2): p. 142-148.
93. Kim, D., et al., Layered Na [Ni 1/3 Fe 1/3 Mn 1/3] O 2 cathodes for Na-ion battery application. Electrochemistry Communications, 2012. 18: p. 66-69.
94. Delmas, C., et al., Structural classification and properties of the layered oxides. Physica B+C, 1980. 99(1–4): p. 81-85.
95. Kuhn, A., et al., Topotactic Oxidation of the Quadruple-Rutile-Type Chain Structure Na 0.875 Fe 0.875 Ti 1.125 O 4. Journal of Solid State Chemistry, 1997. 130(2): p. 184-191.
96. Padhi, A., et al., Effect of structure on the Fe3+/Fe2+ redox couple in iron phosphates. Journal of the Electrochemical Society, 1997. 144(5): p. 1609-1613.
97. Moreau, P., et al., Structure and stability of sodium intercalated phases in olivine FePO4. Chemistry of Materials, 2010. 22(14): p. 4126-4128.
98. Lee, K.T., et al., Topochemical Synthesis of Sodium Metal Phosphate Olivines for Sodium-Ion Batteries. Chemistry of Materials, 2011. 23(16): p. 3593-3600.
99. Kim, H., et al., New iron-based mixed-polyanion cathodes for lithium and sodium rechargeable batteries: combined first principles calculations and experimental study. Journal of the American Chemical Society, 2012. 134(25): p. 10369-10372.
100. Barpanda, P., et al., Sodium iron pyrophosphate: A novel 3.0 V iron-based cathode for sodium-ion batteries. Electrochemistry Communications, 2012. 24: p. 116-119.
101. Barpanda, P., et al., A layer-structured Na 2 CoP 2 O 7 pyrophosphate cathode for sodium-ion batteries. RSC Advances, 2013. 3(12): p. 3857-3860.
102. Feltz, A., et al., Struktur und ionenleitung in festkörpern V: Struktur und eigenschaften der Verbindungen Na3MnZr(PO4)3 und Na3MgZr(PO4)3. Journal of the Less Common Metals, 1988. 137(1–2): p. 43-54.
103. Chakir, M., et al., Synthesis, crystal structure and spectroscopy properties of Na 3 AZr (PO 4) 3 (A= Mg, Ni) and Li 2.6 Na 0.4 NiZr (PO 4) 3 phosphates. Journal of Solid State Chemistry, 2006. 179(6): p. 1883-1891.
104. Richardson, T.J., Phosphate-stabilized lithium intercalation compounds. Journal of power sources, 2003. 119: p. 262-265.
105. Kim, S.-W., et al., A comparative study on Na 2 MnPO 4 F and Li 2 MnPO 4 F for rechargeable battery cathodes. Physical Chemistry Chemical Physics, 2012. 14(10): p. 3299-3303.
106. Kawabe, Y., et al., A comparison of crystal structures and electrode performance between Na2FePO4F and Na2Fe0. 5Mn0. 5PO4F synthesized by solid-state method for rechargeable Na-ion batteries. Electrochemistry, 2012. 80(2): p. 80-84.
107. Nishijima, M., et al., Cathode properties of metal trifluorides in Li and Na secondary batteries. Journal of Power Sources, 2009. 190(2): p. 558-562.
108. Yamada, Y., et al., Liquid-phase synthesis of highly dispersed NaFeF3 particles and their electrochemical properties for sodium-ion batteries. Journal of Power Sources, 2011. 196(10): p. 4837-4841.
109. Wang, L., et al., A superior low-cost cathode for a Na-ion battery. Angew Chem Int Ed Engl, 2013. 52(7): p. 1964-7.
110. Qian, J., et al., Nanosized Na4Fe(CN)6/C Composite as a Low-Cost and High-Rate Cathode Material for Sodium-Ion Batteries. Advanced Energy Materials, 2012. 2(4): p. 410-414.
111. Chen, H., et al., From Biomass to a Renewable LiXC6O6 Organic Electrode for Sustainable Li‐Ion Batteries. ChemSusChem, 2008. 1(4): p. 348-355.
112. Genorio, B., et al., Electroactive Organic Molecules Immobilized onto Solid Nanoparticles as a Cathode Material for Lithium‐Ion Batteries. Angewandte Chemie International Edition, 2010. 49(40): p. 7222-7224.
113. Ratnakumar, B., et al., Organic cathode materials in sodium batteries. Journal of Applied Electrochemistry, 1990. 20(3): p. 357-364.
114. Sakaushi, K., et al., Aromatic porous-honeycomb electrodes for a sodium-organic energy storage device. Nature communications, 2013. 4: p. 1485.
115. Braconnier, J.-J., et al., Comportement electrochimique des phases NaxCoO2. Materials Research Bulletin, 1980. 15(12): p. 1797-1804.
116. Carlier, D., et al., The P2-Na2/3Co2/3Mn1/3O2 phase: structure, physical properties and electrochemical behavior as positive electrode in sodium battery. Dalton Transactions, 2011. 40(36): p. 9306-9312.
117. Jian, Z., et al., Carbon coated Na3V2(PO4)3 as novel electrode material for sodium ion batteries. Electrochemistry Communications, 2012. 14(1): p. 86-89.
118. Koch, N., et al., Influence of water on the work function of conducting poly (3, 4-ethylenedioxythiophene)/poly (styrenesulfonate). Applied physics letters, 2007. 90(4): p. 043512-043512-3.
119. Laforgue, A., Electrically controlled colour-changing textiles using the resistive heating properties of PEDOT nanofibers. J. Mater. Chem., 2010. 20(38): p. 8233-8235.
120. Halik, M., et al., High-mobility organic thin-film transistors based on α, α′-didecyloligothiophenes. Journal of Applied Physics, 2003. 93(5): p. 2977-2981.
121. Kim, J., et al., Enhancement of electrical conductivity of poly (3, 4-ethylenedioxythiophene)/poly (4-styrenesulfonate) by a change of solvents. Synthetic Metals, 2002. 126(2): p. 311-316.
122. Jönsson, S.K.M., et al., The effects of solvents on the morphology and sheet resistance in poly(3,4-ethylenedioxythiophene)–polystyrenesulfonic acid (PEDOT–PSS) films. Synthetic Metals, 2003. 139(1): p. 1-10.
123. Crispin, X., et al., Conductivity, morphology, interfacial chemistry, and stability of poly (3, 4‐ethylene dioxythiophene)–poly (styrene sulfonate): A photoelectron spectroscopy study. Journal of polymer science Part B: Polymer physics, 2003. 41(21): p. 2561-2583.
124. Murugan, A.V., et al., Electrochemical studies of poly (3,4-ethylenedioxythiophene) PEDOT/VS2 nanocomposite as a cathode material for rechargeable lithium batteries. Electrochemistry Communications, 2005. 7(2): p. 213-218.
125. Her, L.-J., et al., Preparation and electrochemical characterizations of poly(3,4-dioxyethylenethiophene)/LiCoO2 composite cathode in lithium-ion battery. Journal of Power Sources, 2006. 157(1): p. 457-463.
126. Arbizzani, C., et al., Li1.01Mn1.97O4 surface modification by poly(3,4-ethylenedioxythiophene). Journal of Power Sources, 2003. 119–121(0): p. 695-700.
127. Yang, Y., et al., Improving the performance of lithium–sulfur batteries by conductive polymer coating. Acs Nano, 2011. 5(11): p. 9187-9193.
128. Mai, L., et al., Cucumber-Like V2O5/poly(3,4-ethylenedioxythiophene)&MnO2 Nanowires with Enhanced Electrochemical Cyclability. Nano Letters, 2013. 13(2): p. 740-745.
129. Lin, C.W., et al., Influence of TiO2 nano-particles on the transport properties of composite polymer electrolyte for lithium-ion batteries. Journal of Power Sources, 2005. 146(1-2): p. 397-401.
130. Lin, Y.-C., et al., Transport Properties of Nano-sized TiO2-based Composite Polymer Electrolyte Prepared by a Green Method. Journal of the Chinese Chemical Society, 2012. 59(10): p. 1250-1257.
131. Carlier, D., et al., The P2-Na2/3Co2/3Mn1/3O2 phase: structure, physical properties and electrochemical behavior as positive electrode in sodium battery. Dalton Trans, 2011. 40(36): p. 9306-12.
132. Venkata Subba Rao, C., et al., Preparation and characterization of PVP-based polymer electrolytes for solid-state battery applications. Iranian Polymer Journal, 2012. 21(8): p. 531-536.
133. Manuel Stephan, A., et al., Characterization of poly(vinylidene fluoride–hexafluoropropylene) (PVdF–HFP) electrolytes complexed with different lithium salts. European Polymer Journal, 2005. 41(1): p. 15-21.
134. Hashmi, S., Natl. Acad. Sci. Lett., 2004. 27: p. 27.
135. Goodenough, J.B. et al., Challenges for Rechargeable Li Batteries†. Chemistry of Materials, 2010. 22(3): p. 587-603.
136. Bhargav, P.B., et al., Structural and electrical properties of pure and NaBr doped poly (vinyl alcohol) (PVA) polymer electrolyte films for solid state battery applications. Ionics, 2007. 13(6): p. 441-446.
137. Solid State Electrochemistry. 1995, Cambridge: Cambridge University Press.
138. Kiran Kumar, K., et al., Investigations on the effect of complexation of NaF salt with polymer blend (PEO/PVP) electrolytes on ionic conductivity and optical energy band gaps. Physica B: Condensed Matter, 2011. 406(9): p. 1706-1712.
139. Hodge, R.M., et al., Water absorption and states of water in semicrystalline poly(vinyl alcohol) films. Polymer, 1996. 37(8): p. 1371-1376.
140. Kumar, D. et al., Ion transport and ion–filler-polymer interaction in poly(methyl methacrylate)-based, sodium ion conducting, gel polymer electrolytes dispersed with silica nanoparticles. Journal of Power Sources, 2010. 195(15): p. 5101-5108.
141. Karan, N.K., et al., Solid polymer electrolytes based on polyethylene oxide and lithium trifluoro- methane sulfonate (PEO–LiCF3SO3): Ionic conductivity and dielectric relaxation. Solid State Ionics, 2008. 179(19–20): p. 689-696.
142. Borghini, M.C., et al., Electrochemical Properties of Polyethylene Oxide ‐ Li [  (  CF 3 SO 2 ) 2 N  ]  ‐ Gamma ‐ LiAlO2 Composite Polymer Electrolytes. Journal of The Electrochemical Society, 1995. 142(7): p. 2118-2121.
143. Cheng, J.-H., et al., Simultaneous Reduction of Co3+ and Mn4+ in P2-Na2/3Co2/3Mn1/3O2 as Evidenced by X-ray Absorption Spectroscopy during Electrochemical Sodium Intercalation. Chemistry of Materials, 2013.
144. Zu, C.-X. et al., Thermodynamic analysis on energy densities of batteries. Energy & Environmental Science, 2011. 4(8): p. 2614-2624.
145. Sauvage, F., et al., Crystal structure and electrochemical properties vs. Na< sup>+</sup> of the sodium fluorophosphate Na< sub> 1.5</sub> VOPO< sub> 4</sub> F< sub> 0.5</sub>. Solid state sciences, 2006. 8(10): p. 1215-1221.
146. Kawabe, Y., et al., Synthesis and electrode performance of carbon coated Na2FePO4F for rechargeable Na batteries. Electrochemistry Communications, 2011. 13(11): p. 1225-1228.
147. Komaba, S., et al., Electrochemically Reversible Sodium Intercalation of Layered NaNi0.5Mn0.5O2 and NaCrO2. ECS Transactions, 2009. 16(42): p. 43-55.
148. Wenzel, S., et al., Room-temperature sodium-ion batteries: Improving the rate capability of carbon anode materials by templating strategies. Energy & Environmental Science, 2011. 4(9): p. 3342-3345.
149. Stevens, D.A. et al., High Capacity Anode Materials for Rechargeable Sodium‐Ion Batteries. Journal of The Electrochemical Society, 2000. 147(4): p. 1271-1273.
150. Hamani, D., et al., NaxVO2 as possible electrode for Na-ion batteries. Electrochemistry Communications, 2011. 13(9): p. 938-941.
151. Senguttuvan, P., et al., Na2Ti3O7: lowest voltage ever reported oxide insertion electrode for sodium ion batteries. Chemistry of Materials, 2011. 23(18): p. 4109-4111.
152. Park, S.I., et al., Electrochemical Properties of NaTi2(PO4)3 Anode for Rechargeable Aqueous Sodium-Ion Batteries. Journal of The Electrochemical Society, 2011. 158(10): p. A1067-A1070.
153. Jian, Z., et al., Carbon coated Na< sub> 3</sub> V< sub> 2</sub>(PO< sub> 4</sub>)< sub> 3</sub> as novel electrode material for sodium ion batteries. Electrochemistry Communications, 2012. 14(1): p. 86-89.
154. Lu, Y., et al., Preparation and characterization of carbon-coated NaVPO< sub> 4</sub> F as cathode material for rechargeable sodium-ion batteries. Journal of Power Sources, 2014. 247: p. 770-777.
155. Shen, W., et al., Towards Highly Stable Storage of Sodium Ions: A Porous Na3V2(PO4)3/C Cathode Material for Sodium-Ion Batteries. Chemistry – A European Journal, 2013. 19(43): p. 14712-14718.
156. Sobkowiak, A., et al., Understanding and Controlling the Surface Chemistry of LiFeSO4F for an Enhanced Cathode Functionality. Chemistry of Materials, 2013. 25(15): p. 3020-3029.
157. Li, W., et al., Understanding the Role of Different Conductive Polymers in Improving the Nanostructured Sulfur Cathode Performance. Nano Letters, 2013. 13(11): p. 5534-5540.
158. Rattan, S., et al., Synthesis of PEDOT:PSS (poly(3,4-ethylenedioxythiophene))/poly(4-styrene sulfonate))/ ngps (nanographitic platelets) nanocomposites as chemiresistive sensors for detection of nitroaromatics. Polymer Engineering & Science, 2013. 53(10): p. 2045-2052.
159. Cheng, J.-H., et al., Simultaneous Reduction of Co3+ and Mn4+ in P2-Na2/3Co2/3Mn1/3O2 As Evidenced by X-ray Absorption Spectroscopy during Electrochemical Sodium Intercalation. Chemistry of Materials, 2013. 26(2): p. 1219-1225.
160. Levi, M.D., et al., Solid‐State Electrochemical Kinetics of Li‐Ion Intercalation into Li1 − x CoO2: Simultaneous Application of Electroanalytical Techniques SSCV, PITT, and EIS. Journal of The Electrochemical Society, 1999. 146(4): p. 1279-1289.
161. Funabiki, A., et al., A.c. impedance analysis of electrochemical lithium intercalation into highly oriented pyrolytic graphite. Journal of Power Sources, 1997. 68(2): p. 227-231.
162. Wang L., et al., Electrochemical Impedance Spectroscopy (EIS) Study of LiNi1/3Co1/3Mn1/3O2 for Li-ion Batteries. Int.J. electrochem. Sci., 2012. 7 ; p. 345 -353