Design polymer/electrolyte interface

Instrumentation. The interface within a suitably constructed electrochemical cell to be investigated is placed in the sample position of a standard DRIFT accessory for an infrared spectrometer for a typical design, see [328,329]. Examples reported so far deal with solid polymer electrolyte fuel cells where the surface of the anode layer exposed to a mixed gas atmosphere containing both water and methanol is separated from the environment via a Cap2 window [331, 332]. Various oxidized species and penetrating methanol were observed. 

The electrodes studied above function over a wide voltage range (0.1 V 4.6 V) which requires the design of electrolytes that are perfectly resistant to oxidation and reduction. Liquid electrolytes and liquid ionic polymers have been considered, primarily to determine the best formulation by trial and error. The study of electrode/electroljde interfaces and the impact of their formiilation on the electrochemical performance of the negative or positive electrode material or even of the system is currently preferred at RS2E rather than the design of new salts or solvents. 

At the interface between the conducting polymer and the ion-selective membrane there is an ionic equilibrium. However, any water present at this interface results in a small volume of internal electrolyte between the conducting polymer and the ion-selective membrane. Variations in the ion concentration of this internal electrolyte can influence the potential of the ISE. The presence of water depends on the conducting polymer and the ion-selective membrane, which should be taken into account in the electrode design. 

Cathode design considerations include the conductivity of the active material its stability relative to various forms of carbon conductors volumetric changes of the reaction products particle size influenced by electrode thicknesses and rate requirements the use of processing aids such as polymers, surfactants, and rheology aids and how the active materials will interface with a current collector. Additionally, in the case of lithium cells, it is critical to conditicm the cathode components prior to cell assembly to remove moisture and volatile process aids which can leach into the organic electrolyte and then react with lithium metal. Such reactions are almost always detrimental to cell impedance and product shelf life. 

A better understanding of intrinsic properties of electrochromic polymer films (such as the electrical, optical and structural properties) and of the tehavior of these films at different interfaces (such as electrode surface and electrolyte solution) will permit in rovement in the design (electrode materials, conq)osition of siq>port electrolyte, contacts, etc.) and performance of ECDs. Usefol information t is needed includes ... 

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