Siloxane Polymer Electrolyte

HIGH CONDUCTIVITY IN AN AMORPHOUS CROSSLINKED SILOXANE POLYMER ELECTROLYTE... 

In view of the low Tg values normally exhibited by poly (siloxanes), several modified forms of these polymers have been tried as hosts in polymer electrolytes [223-228]. The polymers investigated include block copolymers consisting of... 

Lin CC, Chang CB, Wang YZ. Preparation and properties of cross-linked sulfonated poly(imide-siloxane) for polymer electrolyte fuel cell application. J Power Sources 2013 223 277-83. 

Network polymers, which resemble fisherman s nets. For polymer electrolytes, the knots in the nets are often siloxane or isocyanate units and the rope between the knots is PEO-like material. Many polymer electrolytes have been developed from network polymers, as these have been perceived as an attractive way for avoiding crystallinity problems. This topic has been comprehensively reviewed [24, 25, 30, 35, 36]. Irradiation cross-linked linear polymers. Gentle irradiation of a PEO-LiC104 polymer electrolyte by y-rays from a Co source has been used to provide a crystallization-free material with enhanced room temperature conductivity [37-39]. 

Fish, D., Khan, I. M., Wu, E., and Smid, J., Polymer electrolyte complexes of LiC104 and comb polymers of siloxane with oligo-oxyethylene side chains, Br. Polym. J., 20, 281-288 (1988). 

Cui MZ, Li ZY, Zhang J, Feng SY (2008) Siloxane-based polymer electrolytes. Prog Chem 20 1987-1997... 

Siloxane-based electrolytes appear to be an excellent choice due to the low glass transition temperature of many siloxane polymers. The si loxane-based electrolyte described here consists of a methyls loxane backbone with pendent polyether sidechains and crosslinks. Other siloxane electrolytes which have been studied Include a copolymer liquid electrolyte comprised of dimethylsiloxane and ethylene oxide repeat units, and a urethane network of poly(dlmethyIsiloxane grafted ethylene oxide). Initial reports have also appeared on siloxane-... 

The ionic conductivity of the siloxane-based electrolyte described here are as high as any known polymer electrolyte system, and in fact the conductivity is close to that seen in liquid polyether salt solutions. Further increases in conductivity may require a radical change in the nature of the polymer or the salt. 

Block copolymers are introduced into the PEO chain to reduce its regularity. For example, with PS-PEO-PPO block polymer, both the ionic conductivity and the mechanical performance of the prepared electrolytes are better than those of normal PEO because PS and PPO blocks destroy the crystallites in PEO and improve the mechanical strength. Linear block copolymers formed with siloxanes have amorphous structures and the Li+-ionic conductivity can be nearly two orders of magnitude higher. The Tg of the compounds shown in Figure 10.16a and b are -60°C and -123°C, respectively. In the case of their polymer electrolytes formed with LiC104, the ionic conductivities at room temperature are 1.5 x 10 and 2.0 x 10 S/cm, respectively. 

Abstract The interest in sol-gel derived polymer/siloxane hybrid electrolytes has grown considerably during the last decade because of their potential application in sohd state electrochemical devices, in particular batteries and electrochromic devices (ECDs).This review intends to provide an overview of the latest advances in the investigation of the structure, morphology, thermal properties, electrochemical behavior and spectroscopic features of Li -coutaiuiug di-urea crosslinked polyoxyethylene (POE)/siloxane (di-ureasil) electrolytes. Applications of these materials in ECDs will be addressed. 

Synthesis of the siloxanic proton-conducting polymer electrolyte [II] reproduced from Di Noto and Vittadello (2005) by permission of... 

UANG, W.J., KUO, P.L., SoUd polymer electrolytes VIII effect of LiC104-doped level on the microstructure and ionic conductivity of a chemical-covalently polyether-siloxane hybrid electrolyte. Polymer, 2004,45,1617-26. 

Unique combinations of properties continue to be discovered in inorganic and organometallic macromolecules and serve to continue a high level of interest with regard to potential applications. Thus, Allcock describes his collaborative work with Shriver (p. 250) that led to ionically conducting polyphosphazene/salt complexes with the highest ambient temperature ionic conductivities known for polymer/salt electrolytes. Electronic conductivity is found via the partial oxidation of unusual phthalocyanine siloxanes (Marks, p. 224) which contain six-coordinate rather than the usual four-coordinate Si. 

Polymeric electrolytes, polymer-salt complexes, and gelled electrolytes, e.g., benzyl sulfonic acid siloxane, polyethylene oxide (imine, succinate)-LiC104, and PVDF gel in THF containing a mixture of Bu2Mg and AlEtCl2, respectively. 

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