Dissolution polymer electrolytes

Wang XP, Kumar R, Myers DJ. 2006. Effect of voltage on platinum dissolution relevance to polymer electrolyte fuel cells. Electrochem Solid State Lett 9 A225-A227. 

Yasuda K, Taniguchi A, Akita T, loroi T, Siroma Z. 2006b. Platinum dissolution and deposition in the polymer electrolyte membrane of a PEM fuel cell as studied by potential cycling. Phys Chem Chem Phys 8 746-752. 

Systems composed of polymers which have functional groups that can solvate ions, wherein the charge separation required for ionic motion is obtained by dispersion and dissolution of electrolytes in the polymeric matrix. 

SIMULATION OF CORROSIVE DISSOLUTION OF PT BINARY NANOCLUSTER IN ACID ENVIRONMENT OF POLYMER ELECTROLYTE MEMBRANE (PEM) FUEL CELLS... 

Chapter 8 is devoted to the simulation of corrosive dissolution of Pt binary nano-cluster in acid environment, of polymer electrolyte membrane fuel cells. It is well known that under the present catalytic electrode production for low temperature fuel cell, it is necessary to reduce their costs by the proposal of binary platinum nanoclusters PtX (where X are the transition metals Cr, Fe, Co, Ni, Ru), while such nanoparticles may possess high... 

There is as yet no consolidated opinion as to the optimum electrolyte for lithium-sulfiir batteries. Experiments with solid polymer electrolyte are described, but aprotic electrolyte in a Celgard-type separator commonly used in lithium ion batteries is applied more frequently. A large number of electrolytes has been studied that differ both in solvents and the lithium salt. The greatest acceptance was gained by lithium imide solutions in dioxolane (or in a mixture of dioxolane and dimethoxyethane) and also lithium perchlorate solutions in sulfone. Dissolution of polysulfides in electrolyfe is accompanied by a noticeable increase in viscosity and specific resistance of electrolyte. It is the great complexity of the composition of the electrochemical system and that of the processes occurring therein that prevent as yet commercialization of lithium-sulfiir electrolytes. 

Liquid electrolytes cause significant dissolution of the active material, and encourage its diffusion toward the negative electrode. Thus, an alternative is to use polymer electrolytes. ... 

In this case, we have an electrolyte identical to that which is present in lithium-polymer batteries, made of poly(ethylene oxide) (or PEO) in the presence of a lithium salt, solid at ambient temperature, and which needs to be heated above ambient temperature in order for the battery to work (T > 65°C for PEO). Thus, the electrolyte, in its molten state, exhibits sufficient ionic conductivity for the lithium ions to pass. This type of electrolyte can be used on its own (without a membrane) because it ensures physical separation of the positive and negative electrodes. This type of polymer electrolyte needs to be differentiated from gelled or plasticized electrolytes, wherein a polymer is mixed with a lithium salt but also with a solvent or a blend of organic solvents, and which function at ambient temperature. In the case of a Li-S battery, dry polymer membranes are often preferred because they present a genuine all solid state at ambient temperature, which helps limit the dissolution of the active material and therefore self-discharge. Similarly, in the molten state (viscous polymer), the diffusion of the species is slowed, and there is the hope of being able to contain the lithium polysulfides near to the positive electrode. In addition, this technology limits the formation of dendrites on the metal lithium... 

Figure 23.5 is a typical TEM image of a Ft catalyst on a carbon support with polymer electrolyte. The Ft particles, polymer electrolyte, carbon support for the Ft, and voids can be identified clearly. Using EDX and electron diffraction, the elements of the phases and crystal structure can also be determined. TEM has been widely used to measure the catalyst particle size and surface area, to determine Ft dissolution and migration into the membrane, to analyze the catalyst layer structures and catalyst alloy phases, and to identify MEA failures [32-39]. 

Effect of varying poly(styrene sulfonic acid) content in poly(vinylalcohol)-poly(styrene sulfonic acid) blend membrane and its ramification in hydro-gen-oxygen polymer electrolyte fuel cells were investigated. Imaging of the hydrogel formation during the dissolution was performed in a non-invasive way by means of the MRI. Water self-diffusion coefficients and water release kinetics of these materials have been characterized by NMR imaging technique, which validate the use of this membrane in polymer electrolyte fuel cells (PEFCs). 

Sasaki, K., Shao, M. and Adzic, R., Dissolution and Stabilization of Platinum in Oxygen Cathodes , in Polymer Electrolyte Fuel Cell Durability, eds F.N. Btlchi, M. Inaba, and T.J. Schmidt, 7, Springer (2009). 

Rinaldo, S. G., Stumper, J., and Eikerling, M. 2010. Physical theory of platinum nanoparticle dissolution in polymer electrolyte fuel cells. J. Phvs. Cham. C. 114(13), 5773-5785. 

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