Effects of Electrolyte on Redox Potentials

Abstract

Redox potentials, especially as measured by cyclic voltammetry and related electrochemical techniques, are the basis for understanding energetics of photochemical solar energy storage, organic photovoltaics, light-emitting diodes, and even photosynthesis. These very popular techniques are dominant although none of the energy systems just mentioned contain large concentrations, typically 100 mM, of supporting electrolyte needed for electrochemical techniques to work. At the same time, the added electrolytes often have large, but unknown effects on the energetics studied. Despite substantial efforts using microelectrodes, it has not been possible to utilize electrochemical techniques to measure redox potentials in the absence of electrolytes. This chapter will be an account of new techniques applying the method of pulse radiolysis to partly answer the question: what is the effect of electrolytes on redox potentials?

Coral-Shaped Bifunctional NiCo2O4 Nanostructure: A Material for Highly Efficient Electrochemical Charge Storage and Electrocatalytic Oxygen Evolution Reaction

“…The stable and high capacitance values are achieved because of faster electrolyte ion diffusion through the electrode/electrolyte interface, resulting in favorable faradaic reactions. The response time (τ o ) which is related to the faster ion faradaic reaction behavior can be evaluated from the EIS plot using the Millers method and knee frequency as reported earlier. , The response time is the reciprocal of the response frequency ( f o ) determined from the Bode plot (Figure S13a, Table ). The response time for the highly porous coral-like NiCo 2 O 4 electrode was found to be 90 s. This small value of the response time signifies a faster ion exchange mechanism in the aqueous KOH electrolyte across the electrode/electrolyte interface, which causes rapid faradaic reactions to take place at the NiCo 2 O 4 electrode (NCO24), thus yielding higher and stable supercapacitance values. ,, …”