Double Layer Structural Effects in Cyclic Voltammetry Curves Complicated with Non-Equilibrium Injection of Charge Carriers into Redox Polymer Films

Anishchenko, Dmitrii V.; Levin, Oleg V.; Malev, V. V.

doi:10.1016/j.electacta.2017.04.095

Cited by 10 publications

(10 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…25 This implies that diffusion is not a rate-determining step of the charging process, thus we focus on slow charge transfer kinetics. 42 Additionally, the decrease in the electrolyte concentration leads to a rapid shift in the anodic peak, while the cathodic one shifts insignificantly Figure 12a, which may be due to slow anion desolvation accompanying intercalation. Therefore, we make an assumption of slow anion intercalation being the ratedetermining step for the experimental system under consideration.…”

Section: Resultsmentioning

confidence: 98%

“…To name a few, slow diffusion within the active material, slow diffusion of ions within the electrolyte of the pores of the active material, 7 electron charge transfer at the redox material/metal substrate interface, and slow ion injection at the redox material/electrolyte solution interface. 42 The CV method is known to be an insightful tool for understanding the nature of the electrochemical process and its rate-determining steps. Langmuir−Frumkin or reformulated isotherms are often used as the thermodynamic basis for modeling CV diagrams complicated by different rate-limiting processes.…”

Section: Resultsmentioning

confidence: 99%

“…Langmuir−Frumkin or reformulated isotherms are often used as the thermodynamic basis for modeling CV diagrams complicated by different rate-limiting processes. 20,42,43 Any of the above-mentioned possible limiting processes being sufficiently slow causes non-equilibrium aspects of CV behavior: the cathodic branch of the CV is not a mirror reflection of the anodic branch. Additionally, each slow process has its own characteristic features.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, we cannot perform direct comparison between proposed theory and experimental CV curves without accounting for kinetic limitations. 42 However, some preliminary conclusions can be made: 1. Experimental CVs have a clear tendency to shift toward positive potentials with decreasing electrolyte concentration.…”

Section: Resultsmentioning

confidence: 99%

“…There is a variety of different processes, which can possibly limit the performance of the redox system. To name a few, slow diffusion within the active material, slow diffusion of ions within the electrolyte of the pores of the active material, electron charge transfer at the redox material/metal substrate interface, and slow ion injection at the redox material/electrolyte solution interface . The CV method is known to be an insightful tool for understanding the nature of the electrochemical process and its rate-determining steps.…”

Section: Results and Discussionmentioning

confidence: 99%

See 4 more Smart Citations

New Variant of Electrochemical Intercalation Isotherm: Analysis of Instability Region Dependence on Electrolyte Concentration

et al. 2022

View full text Add to dashboard Cite

Electroactive redox materials, encompassing redox polymers, metal−organic frameworks, and intercalation materials, play an important role in a wide range of emerging applications. However, many theoretical issues concerning quantitative thermodynamic description of such materials remain unclear so far. Existing variants of electrochemical intercalation isotherms (namely, the Langmuir−Frumkin isotherm, which often applies to redox polymers and electroactive solid materials, and the reformulated isotherm, accounting for the phase character of the potential distribution within the material) do not explain the dependence of redox materials' voltammetric responses on the electrolyte concentration. In addition to that, studies show that the reformulated isotherm has a higher value of the so-called shortrange interaction parameter at which phase separation starts and asymmetric single-phase regions in comparison to the Langmuir− Frumkin isotherm. A simple modification, accounting for the possibility of both positive and negative ions of the electrolyte solution to intercalate the electroactive redox material, leads to a new variant of electrochemical intercalation isotherm, which includes Langmuir−Frumkin and reformulated isotherms as limiting cases. The new model explains the dependence of redox materials' voltammetric responses on the electrolyte concentration. Theory predicts the dependence of short-range interaction parameters at which phase separation starts on the electrolyte composition. Thus, the new electrochemical intercalation isotherm shows the dependence of its unstable, metastable, and stable regions on the electrolyte concentration and ion distribution coefficients. It opens up a possibility to tune material characteristics such as sizes of single-phase/two-phase regions. In some particular cases, it is possible to induce or eliminate the phase transition by changing the concentration of the electrolyte. We believe that studying such properties may help in future realization of new smart materials with superior characteristics for electrochemical energy storage, use in chemical sensors, medical applications, and so forth.

show abstract

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%