Polymer cathodes

The development of a rechargeable polymer battery is being pursued worldwide. Its attraction lies in the specific weight of polymers, which is considerably lower than that of ordinary inorganic materials, as well as potential environmental benefits. In principle there are three different types of battery. The active polymer electrode can be used either as cathode (cell types 1, 2), or as anode (cell type 3), or as both cathode and anode (cell type 4) (Fig. 14). As the most common polymer materials are usually only oxidizable, recent research has concentrated on developing cells with a polymer cathode and a metal anode. 

Concentrating on polymer cathodes, materials have been engineered that exhibit ... 

M(crypt)] (polymer) + (cathode) - crypt(polymer) -l- M (cathode). 

Configuration of EL device (anode/EL polymer/cathode) Relative EL quantum efficiency Turn-on voltage (V) Light intensity (cd/m2)... 

Pokhodenko VD, Koshechko VG, Krylov VA. New electrolytes and polymer cathode materials for lithium batteries. J Power Sources 1993 45 1-5. 

The devices used for the EL and PL measurements were fabricated in the thin film sandwich configuration anode/polymer/cathode. The electronic structure of alkoxy derivatives of PPV has been studied via internal field emission [42], internal photoemission [76], cyclovoltammetric spectroscopy [159]) and photoelectron spectroscopy [160]. The data indicate that the bottom of the Tr -band and the top of the ir-band are at 3 eV and 5 eV respectively, with respect to the vacuum. Thus, relatively good hole and electron injection can be achieved by using transparent indium/tin-oxide (ITO) as the anode and calcium (Ca) or barium (Ba) as the cathode [42,161]. In practice, however, hole injection is very sensitive to the quality of the ITO. A thin layer (= 300 A) of conducting polymer provides excellent, reproducible hole injecting contacts [70,71,162]. 

It is known that the polymer chains are lying in the plane of the surface.34 In a typical polymer device structure anode/polymer/cathode, the charge carriers are traveling across the polymer film, which is perpendicular to the plane of the film. Therefore, the conductivity of the film will, to a large extent, depend on the rate for interchain hopping of the carriers or on the rate for the interchain electron transfer. If a polymer film is dominated by the Ar-type aggregation style shown in Fig. 6.4, where the bulky side chains (the insulators) are trapped inside the aggregate and... 

Suga T., Konishi H. and Nishida H. (2007), Photocrosslinked nitroxide polymer cathode-active materials for application in an organic-based paper battery , Chem. Comm., 1730-1732. 

A similar approach can be taken to study electron injection. Replacing ITO with a lower work function metal (e. g. Nd or Mg) yields devices in which the carriers are almost exclusively electrons. A similar analysis of the data from a range of electron-only devices indicates that electrons tunnel into the jt -band of MEH-PPV at 4.9 eV through a triangular barrier at the polymer/cathode interface. 

Guo, W.,Yin, Y.-X.,Xm, S., Guo,Y.-G., Wan, L.-J., 2012. Superior radical polymer cathode material with a two-electron process redox reaction promoted by graphene. Energy Environ. Sci. 5,5221-5225. 

It is interesting to use the polymer cathodes in lithium-ion cell types. This concept has been exploited by assembling cells having the structure C/LiC104-EC-PC-PMMA/PPy. 

Prymak, J.D. 2001. Improvements with polymer cathodes in aluminum and tantalum capacitors. Vol. 2. Applied Power Electronics Conference and Exposition, 16th Annual IEEE Anaheim, p. 1210. 

Chattaraj, A., et al. 1993. Improved conducting polymer cathodes for lithium batteries. J Power... 

Prymak, J.D. 1998. Conductive polymer cathodes - The latest step in declining ESR in tantalum capacitors, IEEE Industry Applications Society Annual Meeting, lEEE-IAS, St.Louis. 

U. Merker, K. Reuter, K. Wussow, S. Kirchmeyer and U. Tracht, PEDOT as conductive polymer cathode in electrolytic capacitor, in Proceedings of the 16th Passive Components Conference CARTS Europe, Nice, 2002, p. 71. 

PT is also an excellent stable electrode material. The characteristics of PT as a stable polymer cathode material for organic batteries were studied < "2). 

ECA SP 4984 Surface Mount Aluminum Electrolytic Chip Capacitor with Polymer Cathode... 

Carbon agglomerate Polymer Cathode catalyst Gas diffusion Pt particle ° membrane layer layer... 

Saito, T., Merrill, M.D., Watson, V.J., Logan, B.E. Hickner, M.A. Investigation of ionic polymer cathode binders for microbial fuel-cells. Electrochim. Acta 55 (2010), pp. 3398-3403. 

FIGURE 34.30 Schematic illustration of thin, flat rechargeable Uthium battery with sulfur-based polymer cathode material. (From Ref. 56.)... 

Kim J-K, Cheruvally G, Choi J-W et al (2007) Effect of radical polymer cathode thickness on the electrochemical performance of organic radical battery. Sohd State Ionics 178(27-28) 1546-1551... 

KoshikaK, Sano N, Oyaizu K et al (2009) An aqueous, electrolyte-type, rechargeable device utilizing a hydrophilic radical polymer-cathode. Macromol Chem Phys 210(22) 1989-1995... 

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