Changes In Ionic Conductivity Research Articles

Substituent effects on the photoreactivity of Ru-containing ionic liquids exhibiting reversible ionic conductivity changes

Controlling the ionic conductivity of liquids using external fields is crucial for electronic device applications. We have recently developed metal-containing ionic liquids (ILs) exhibiting reversible ionic conductivity changes upon UV photoirradiation and heating based on the photochemical oligomerization reaction of sandwich Ru complexes. In this study, to explore the controllability of the reaction, we synthesized several Ru-containing ILs with different substituents containing a cyano or dimethylamino group at the terminal position. The photochemical reaction was significantly affected by the coordination ability and flexibility of the substituents, and mixing ILs having different reactivity allowed controlling the conversions. Upon successive photoirradiation–heating cycles, the ionic conductivity of these ILs underwent reversible changes, whose extent reflected the photoreactivity of the ILs.

Ion Transport and Dielectric Studies on [PEO:TiO2]:NH4SCN Nanocomposite Polymer Electrolytes

AbstractAn improvement in ion transport behavior and dielectric properties of polyethylene oxide based polymer electrolytes have been investigated upon the dispersal of TiO2 nanoparticles. TiO2 nanoparticle is synthesized with the help of well‐known sol–gel technique. The different compositions of polymer electrolyte systems are prepared by the solution cast technique. Nanocomposite polymer electrolytes (NCPEs) films are synthesized by loading of nanoTiO2 particle in a pristine polymer electrolyte matrix. The structural and morphological behaviors of nanocomposite polymer electrolytes (NCPEs) have been subsequently characterized by XRD and SEM studies. The ionic behavior of synthesized NCPEs is ascertained by Wagner's polarization technique. AC and DC conductivity of polymer electrolyte films have been carried out using impedance spectroscopic techniques. Dielectric relaxation studies of polymer electrolytes are examined using impedance spectroscopic data. The conductivity relaxation mechanism of NCPEs has been concluded with the help of modulus formalism. DC conductivity of best ion‐conducting NCPEs at room temperature has been found to σ = 2.5 × 10−5 S cm−1. The electrode polarization effect has completely vanished in the dielectric and modulus formalism and the conductivity scaling data show a single master curve observed in ion dynamics. The change in ionic conductivity with frequency and temperature is studied by impedance spectroscopic investigations. The effect of salt on dielectric parameters of NCPEs is also extracted from impedance spectroscopic data to explore underlying ion dynamics.

Electrorheological effect and dielectric properties of Poly(ionic liquid) microspheres with different length of alkyl chain spacer between ion pair and backbone

Imidazolium-based poly(ionic liquid) analogues having different lengths of alkyl chain spacer between ion pair and backbone, named as P[ECnVim][PF6] (n = 2, 3, 6), were synthesized. Then, P[ECnVim][PF6] were transformed into microspheres by an evaporation-induced phase separation method. The influence of the length of alkyl chain spacer on the electro-responsive electrorheological effect and dielectric property of P[ECnVim][PF6] microsphere suspensions were studied. It showed that as the length of alkyl chain spacer increased, the electrorheological effect increased but the working temperature range of electrorheological effect became narrow. By combining dielectric spectra analysis and activation energy measurement, it was clarified that the influence of the length of alkyl chain spacer on electrorheological effect was mainly associated with the change of ionic conductivity and interfacial polarization, which was further related to the change of elastic potential energy of ion motion in P[ECnVim][PF6] with different lengths of alkyl chain spacer between ion pair and backbone. However, the working temperature range of electrorheological effect depended on the change of glass transition temperature with the length of alkyl chain spacer. The result provides the structure-property relationship insight for the design of poly(ionic liquid)-based electro-responsive electrorheological materials.

New organic ionic plastic crystals based on pyrrolidinium dication for a solid‐phase electrolyte

AbstractA series of 1,4‐bis(N‐alkylpyrrolidinium)butane salts combined with Br−, I−, PF6−, and Tf2N− anions were newly designed and synthesized. In nonpolar CDCl3 solution, the axial and equatorial proton peaks of the bis‐pyrrolidinium cation ring are distinguished in 1H NMR. Also, the strengths of ion paring could be estimated from the 1H NMR chemical shift changes of the bridge and pyrrolidinium proton peaks. 1,4‐Bis(N‐hepthylpyrrolidinium)butane I− is an organic ionic plastic crystal showing the lowest fusion entropy value (ΔSf = 3.4 J K·mol−1). Softer crystalline morphologies were found by polarized optical microscope images at plastic crystal phase of each sample and the results were corresponding to differential scanning calorimetry results. 1,4‐Bis(N‐ethylpyrrolidinium)butane Tf2N− showed the softest crystal phase. Ionic conductivity changes and electrochemical stabilities of the bis‐pyrrolidinium PF6− and Tf2N− salts were also measured, and they were stable up to 4.3 V (vs. Li/Li+) and expected to be applied as an electrolyte component.

Insights from an electro-mechanical heart failure cell model: Role of SERCA enhancement on arrhythmogenesis and myocyte contraction

Background and objectiveStructural and electrical remodeling in heart failure predisposes the heart to ventricular arrhythmias. Computer modeling approaches, used to complement experimental results, can provide a more mechanistic knowledge of the biophysical phenomena underlying cardiac pathologies. Indeed, previous in-silico studies have improved the understanding of the electrical correlates of heart failure involved in arrhythmogenesis; however, information on the crosstalk between electrical activity, intracellular Ca2+ and contraction is still incomplete. This study aims to investigate the electro-mechanical behavior of virtual failing human ventricular myocytes to help in the development of therapies, which should ideally target pump failure and arrhythmias at the same time. MethodsWe implemented characteristic remodeling of heart failure with reduced ejection fraction by including reported changes in ionic conductances, sarcomere function and cell structure (e.g. T-tubules disarray). Model parametrization was based on published experimental data and the outcome of simulations was validated against experimentally observed patterns. We focused on two aspects of myocardial dysfunction central in heart failure: altered force-frequency relationship and susceptibility to arrhythmogenic early afterdepolarizations. Because biological variability is a major problem in the generalization of in-silico findings based on a unique set of model parameters, we generated and evaluated a population of models. ResultsThe population-based approach is crucial in robust identification of parameters at the core of abnormalities and in generalizing the outcome of their correction. As compared to non-failing ones, failing myocytes had prolonged repolarization, a higher incidence of early afterdepolarizations, reduced contraction and a shallower force-frequency relationship, all features peculiar of heart failure. Component analysis applied to the model population identified reduced SERCA function as a relevant contributor to most of these derangements, which were largely reverted or diminished by restoration of SERCA function alone. ConclusionsThese simulated results encourage the development of strategies comprising SERCA stimulation and highlight the need to evaluate both electrical and mechanical outcomes.

Effect of polyvinyl alcohol to starch ratio on the nutrient release and water absorption behaviour of slow release fertiliser

In the present study, polyvinyl alcohol (PVA) has been blended with starch to confine the fertiliser particles in the polymer matrix. NPK fertiliser particles have been embedded in polymer matrix by a solution casting method. Different weight ratios of PVA to starch, that are 7:3, 5:5 and 3:7 have been investigated. Morphologies of the samples have been studied using optical microscopy. Higher content of PVA in composition leads to a smooth surface of film. The prepared samples have been characterised by ionic conductivity measurements and water absorption tests to estimate the fertiliser release rate and water retention capacity, respectively. Sample containing higher content of PVA shows lower change in ionic conductivity and hence, lower release of nutrients in 24 h of soaking in distilled water. Among the three samples, composition having PVA to starch ratio of 5:5 shows uniform surface, higher water retention characteristics and thereby, better slow release capabilities.

Current Status and Future Directions in Environmental Stability of Sulfide Solid-State Electrolytes for All-Solid-State Batteries

Recently, sulfide-based solid-state electrolytes (SSEs) have attracted much attention owing to their high ionic conductivity and feasible mechanical features. The environmental stability of sulfide-based SSEs is one of the critical aspects due to the possible decomposition, and ionic conductivity change will affect the fabrication and electrochemical performance of the batteries. Thus, important efforts have been made to reveal and improve their environmental stability, and a timely summary of the progress is urgently needed. In this review, we first clarify the definition of environmental stability and its significance in the context of practical use. After indicating the degradation mechanisms of sulfide-based SSEs, we summarize several effective strategies to improve their stability and also highlight the related theoretical studies. The stability of organic solvents of sulfide SSEs is also summarized and discussed, which may help reliable sulfide SSEs in the battery system. The main target of this review is to gain insights and provide useful guidance to further improve the environmental stability of sulfide SSEs, which will finally promote the commercialization of sulfide-based all-solid-state batteries.

Surface and Structure of Phosphatidylcholine Membranes Reconstructed with CoFe2O4 Nanoparticles.

Structural changes in phosphatidylcholine lipid membranes caused by the introduction of insoluble CoFe2O4 nanoparticles (NPs) are analyzed. Changes in nuclear magnetic resonance spectrum, infrared spectrum, and ionic conductivity of membranes are observed with the addition of NPs. The presence of NPs in membranes is proved by atomic force and magnetic force microscopy. Structural changes in the membranes in the vicinity of the lipid C-O bonds caused by NPs are observed by Scanning near-field optical microscopy. Analysis of nuclear magnetic resonance (NMR) spectra allowed us to identify the affected atomic groups in the membrane surface layers. Conductivity measurements of the bilayer membranes were performed in DC as well as in time-resolved modes. Hydrophobic NPs stimulate surface distortion and creation of pores, which depending on NP concentration leads to an increase in the ionic conductivity of membranes. Concentration dependence demonstrating percolation threshold was analyzed in the frame of the fractal theory approach.

Electron diffraction study and ionic conductivity of fluorite Ba1-xLaxF2+x and tysonite La1-yBayF3-y phases in the BaF2-LaF3 system

Crystals of fluorite phases with the CaF2 structure: Ba1−xLaxF2+x (x = 0, 0.05, 0.105, 0.25, 0.35, 0.40) and those of tysonite ones with the LaF3 structure: La1−yBayF3−y (y = 0, 0.05, 0.09) have been studied by electron diffraction and elemental analysis in a transmission electron microscope. Diffraction patterns of Ba1−xLaxF2+x crystals with x = 0.105, 0.25 exhibit diffuse scattering, which indicates the presence of clusters of structural defects. Blurred supercell reflections are seen in diffraction patterns of Ba1−xLaxF2+x crystals with a high lanthanum content (x = 0.35, 0.40) in addition to diffuse scattering. They indicate the existence of nanoscale ordered crystallites as well as clusters. It was found that LaF3 and the tysonite phase La1−yBayF3−y with a low barium content (y = 0.05) is of a low-temperature l-form (space group P3¯c1, Z = 6). A small fraction of tysonite crystallites in La1-yBayF3-y crystals with y = 0.09 is of a high-temperature h-form (space group P63/mmc, Z = 2). An intermediate crystal structure between l- and h-forms was also found.The maximum ionic conductivity σdc of tysonite crystals La1−yBayF3−y at 293 K is 800 times higher than that of fluorite ones Ba1−xLaxF2+x. A correlation was found between logarithm of conductivity and composition: lg σdc(x) = ax + b for fluorite Ba1−xLaxF2+x and tysonite La1−yBayF3−y crystals. The reason for the additive law of change in ionic conductivity in both types of nonstoichiometric phases in the BaF2-LaF3 system is apparently the similarity of defect structures of fluorite and tysonite phases.

Quantitative Analysis of H+ Transportation of Nafion film on Different Substrate using Planar Inter Digitated Electrodes

Introduction: Ionomer thin-film gained attraction because of their thickness- and morphology-dependent changes in ionic conductivity. In a fuel cell catalyst layer, ionomer thin films coating the carbon-supported Pt-based catalysts (Pt/C) is distributed in spatially heterogeneous manner with variation in thickness and connectivity. Thus, it is difficult to clarify the quantitative attribution of the true source of effective proton resistance among Pt and carbon-support. To evaluate the quantitative attribution of proton conductivity of a thin-film ionomer on relevant substrates (e.g., carbon), we have fabricated specially designed interdigitated electrodes (IDEs) to accommodate different substrates upon which ionomer film is coated. In this work, we present the Nafion (~55 nm) proton (H+) transportation over carbon and quartz substrate in N2 atmosphere. Also, we will discuss the true attribution of substrate-dependence to estimate the Nafion’s thin film conductivity. Experimental: Interdigitated electrodes (IDEs) with and without carbon pad were fabricated in clean room facilities. To prepare IDEs, the patterned carbon structure was developed and pyrolyzed at 1000 ºC in 2% H2/N2 gas before the Pt deposition. 1.2% Nafion dispersion was spin coated and dried at 40ºC under vacuum before electrochemical impedance spectroscopy (EIS) measurement in N2 atmosphere. Relative humidity (RH) dependence of in-plane H+ resistance was obtained and discussed through EIS measurements. Results and Discussion: Figure 1 (a) and (b) shows the side view of IDEs with (Pt_C_IDE) and without carbon pad (Pt_Q_IDE), and also Nafion’s (~55 nm) H+ resistance obtained from EIS measurement at various RH in N2 atmosphere. Nyquist plot (not shown) exhibited significant difference and ascribed film resistance (Mean value) for ionomer at carbon substrate was significantly lower (one order of magnitude) compared to that at the quartz substrate, as shown in Fig. 1 (c).In case of H+ resistance using Pt IDE with carbon (Pt_C_IDE), approximately 90% of the IDE area between the electrodes is carbon and the rest is quartz. Therefore, the method of estimation of Nafion’s thin film conductivity from impedance response must be reviewed carefully and will be discussed later in detail.

Evaluations of Thermal Diffusivity and Electrochemical Properties for Lithium Hydride and Electrolyte Composites

There is ongoing research to develop lithium ion batteries as sustainable energy sources. Because of safety problems, solid state batteries, where electrolytes are replaced with solids, are attracting attention. Sulfide electrolytes, with a high ion conductivity of 10-3 S/cm or more, have the highest potential performance, but the price of the main materials is high. This study investigated lithium hydride materials, which offer economic advantages and low density. To analyze the change in ion conductivity in polymer electrolyte composites, PVDF, a representative polymer substance was used at a certain mass ratio. XRD, SEM, and BET were performed for metallurgical analyses of the materials, and ion conductivity was calculated through the EIS method. In addition, thermal conductivity was measured to analyze thermal stability, which is a major parameter of lithium ion batteries. As a result, the ion conductivity of LiH was found to be 10-6 S/cm, and the ion conductivity further decreased as the PVDF ratio increased when the composite was formed.

Critical Percolation Threshold for Solvation Site Connectivity in Polymer Electrolytes Mixtures

To address the tradeoff between mechanical strength and Li+ conductivity in Poly(Ethylene Oxide) (PEO)-based electrolytes, a rigid nonconductive polymer is frequently added to the electrolyte via blending or copolymerization. The ionic conductivity of mixed PEO electrolytes is generally lower than that of unmixed PEO electrolytes. The suppressed ionic conductivity is attributed to the reduced segmental mobility and connectivity of the conductive PEO cites. Most experimental systems make it difficult to decouple the two mechanisms and accurately examine their impact on conductivity. We compare two symmetric polymer mixtures (50:50 wt%): a miscible polymer blend PEO/PMMA and a disordered block copolymer (BCP) PEO-b-PMMA, both with the same amount of Li salt. Because their chemical and physical properties are the same, changes in ionic conductivity can be attributed solely to local changes in PEO network connectivity. We discover that the mixtures' immediate Li+ solvation sites (<5 Å) are identical to those of unmixed PEO electrolytes. The presence of non-conducting PMMA near the PEO, on the other hand, causes local concentration changes at longer range scales. The BCP is more mixed than the blend electrolyte at these length scales, resulting in a factor of two drop in conductivity. To that end, we propose a quantitative computational model that considers Li+ transport within and across PEO clusters at the appropriate length scales. This new understanding of network connectivity in polymer electrolyte mixtures is critical for the design of future multiphase polymer electrolyte systems.

(Invited) Electro-Chemo-Mechanics at Solid Electrolyte-Cathode Interfaces

Strain is present at interfaces of solid electrolytes with cathode and anode in solid state batteries due to interfacial reactions and due to volumetric expansion and contraction of the electrodes during battery charge and discharge cycles. In this talk, first, I will present our findings on how a solid electrolyte-cathode interface degrades chemically and electrochemically, and its implications on the interface mechanical degradation. In particular, we have studied the garnet type Li7La3Zr2O12 (LLZO) solid electrolyte with thin film LiNi0.6Mn0.2Co0.2O2 (NMC622) cathode as a model system to enable interface sensitivity. X-ray absorption spectroscopy, X-ray diffraction and Gibbs free energy analysis have enabled us to identify the chemical and electrochemical degradation pathways, and their implication on the mechanical instability at the interface. Second, is the reverse effect of such mechanical evolution, in particular the effect of elastic strain at the interface on Li-ion diffusion in the solid electrolyte. For this question, we have taken a model solid electrolyte, β-Li3PS4, and have performed Ab Initio Molecular Dynamics (AIMD) simulations to resolve the resulting changes in Li site stability and Li ion conductivity under different strain tensors. We have found that the strain tensors which compress the c-axis (+2% ab, –2% ac, –2% bc, –2% isotropic) increase the Li-ion diffusivity, and the strain tensors which stretch the c-axis (–2% ab, +2% ac, +2% bc, +2% isotropic) reduce it. The c-axis compression increases disorder in the lattice and promote jumps along all migration pathways. The results show that elastic strain can promote Li disorder and superionic conductivity, with an effect on Li-ion diffusion comparable to that of chemical doping, and is important to consider for accurate understanding and prediction of solid-state Li-ion battery interface properties.

Analytical analysis of concentration of charge carriers in polymer electrolytes through different models

The development of solid polymer electrolytes with high ionic conductivity and good chemical and mechanical stability for application in various electrochemical devices has been a critical area of research in the past few decades. For the better performance of the electrochemical devices, the compatibility between the electrodes and electrolytes of the system is the foremost requirement. In addition to this, the ion conductivity of the electrolytes is an important parameter. Understanding the mechanism of changes in ionic conductivity with different concentrations of salt and dispersoid is very crucial. In the present work, we have used three theoretical models, the Rice-Roth model, the Trukhan model and Schutt and Gerdes Model, to understand the reasons behind the variation in conductivity by calculating the concentration and mobility of charge carriers. All the required parameters of the model for the calculation purpose have been taken from Impedance Spectroscopy data. The Trukhan model is a direct method for evaluating the exact value of the diffusion coefficient. The diffusion coefficient of PEO-NaI based electrolyte thin films are calculated from the dielectric tangent loss and further used for analyzing the concentration of charge carrier and ion mobility. Similarly, two more theoretical models, Rice-Roth and Schutt & Gerdes model were used to confirm the value of the number of charge carriers. Further, all the results are compared with each other for the conclusion.

Influence of sodium inward current on the dynamical behaviour of modified Morris-Lecar model

This paper presents a modified Morris-Lecar model by incorporating the sodium inward current. The dynamical behaviour of the model in response to key parameters is investigated. The model exhibits various excitability properties as the values of parameters are varied. We have examined the effects of changes in maximum ion conductances and external current on the dynamics of the membrane potential. A detailed numerical bifurcation analysis is conducted. The bifurcation structures obtained in this study are not present in existing bifurcation studies of original Morris-Lecar model. The results in this study provides the interpretation of electrical activity in excitable cells and a platform for further study.

Refinement of Active and Passive Membrane Properties of Layer V Pyramidal Neurons in Rat Primary Motor Cortex During Postnatal Development.

Achieving the distinctive complex behaviors of adult mammals requires the development of a great variety of specialized neural circuits. Although the development of these circuits begins during the embryonic stage, they remain immature at birth, requiring a postnatal maturation process to achieve these complex tasks. Understanding how the neuronal membrane properties and circuits change during development is the first step to understand their transition into efficient ones. Thus, using whole cell patch clamp recordings, we have studied the changes in the electrophysiological properties of layer V pyramidal neurons of the rat primary motor cortex during postnatal development. Among all the parameters studied, only the voltage threshold was established at birth and, although some of the changes occurred mainly during the second postnatal week, other properties such as membrane potential, capacitance, duration of the post-hyperpolarization phase or the maximum firing rate were not defined until the beginning of adulthood. Those modifications lead to a decrease in neuronal excitability and to an increase in the working range in young adult neurons, allowing more sensitive and accurate responses. This maturation process, that involves an increase in neuronal size and changes in ionic conductances, seems to be influenced by the neuronal type and by the task that neurons perform as inferred from the comparison with other pyramidal and motor neuron populations.

Chemical physics insight of PPy-based modified ion exchange membranes: A fundamental approach

Four commercially available, cost-effective ion exchange membranes (two cationic and two anionic exchange membranes, CEMs and AEMs, respectively) were modified to mitigate crossover phenomena of the redox active species typically observed in Aqueous Organic Redox Flow Batteries (AORFB) systems. The modification strategy was carried out using a pyrrole(Py)-based polymer which successfully reduced the permeation of two redox active organic molecules, a viologen derivative (named BP7 throughout this study) and TEMPOL, by an order of magnitude. Additionally, modified membranes showed not significant changes in ion conductivity, with negligible effect on the electrical conductivity of the membranes at a given conditions. The morphology, physicochemical, mechanical, and electrochemical properties of the membranes were determined to evaluate the impact of these modifications. AEMs modified in this manner were found to have optimal properties, showing an increase in ion exchange capacity while maintaining excellent mechanical stability and unaltered permselectivity. Additionally, the diffusion boundary layer of these AEMs was slightly extended, which suggests a greater double layer stability for ion exchange processes than in the case of CEMs. Our work shows that these modified membranes could be an appealing approach for AORFB applications.

Influence of molecular weight on electro-responsive electrorheological effect of poly(ionic liquid)s: Rheology and dielectric spectroscopy analysis

Poly[methylmethacrylate trimethylamine][hexafluorophosphate] (P[MTMA][PF6]) poly(ionic liquid)s (PILs) with different molecular weight (polymerization degree N = 6–652) were synthesized by free-radical polymerization. The influence of molecular weight on the electrorheological (ER) effect of P[MTMA][PF6] particles dispersed in insulating carrier liquid was studied by rheological test, and the reasons behind the influence was analyzed by dielectric spectroscopy. The result shows that when the molecular weight of P[MTMA][PF6] is less than ∼30,000 (N<∼100), the ER effect is sensitive to the molecular weight and it increases as the molecular weight increases; when the molecular weight exceeds ∼30,000 (N>∼100), the ER effect tends to saturate. Dielectric spectra analysis shows that the influence of molecular weight on the ER effect of P[MTMA][PF6] is closely related to the interfacial polarization and the leaking conduction of P[MTMA][PF6], which further depends on the changes of ionic conductivity of P[MTMA][PF6] particles and dissolution ability of P[MTMA][PF6] particles in carrier liquid with molecular weight. By activation energy calculation and XRD analysis, it demonstrates that the molecular level reason for the influence of molecular weight on conductivities, polarization and ER effect is related to the changes of the elastic potential energy of P[MTMA][PF6] matrix and the limiting ability of matrix for ion dissolution in carrier liquid with the molecular weight.

Towards the application of carboxymethyl chitin/ionic liquid blend as polymer electrolyte membrane for aqueous batteries

Carboxymethyl chitin (CMChit) has the potential to be used as a solid polymer electrolyte (SPE) based on its ionic conductivity value of the order of 10−6 S·cm−1 in self-standing membranes. In controlled humidity of 65RH%, carboxymethyl chitin based membrane blended with 1-Butyl-3-methylimidazolium acetate (BMIM[Ac]) ionic liquid (IL) (40 wt%) showed a threshold value of ionic conductivity in the order of 10−4 S·cm−1 and electrochemical stability was up to 2.93 V. The effects of the relative humidity and ionic liquid weight fraction on the ionic conductivity and structural changes were investigated in detail. Furthermore, the X-ray diffraction (XRD) diffractogram indicated a clear reduction of crystallinity of the CMChit. The Field-emission scanning electron microscopy (FESEM) observation of the cross-sections confirmed the homogeneity of the prepared blend. This electrolyte was tested in symmetric cells based on Zn//SPE//Zn and showed good reversibility and potential for application in proton-conducting batteries.

Deterministic and Stochastic Cellular Mechanisms Contributing to Carbon Monoxide Induced Ventricular Arrhythmias.

Chronic exposure to low levels of Carbon Monoxide is associated with an increased risk of cardiac arrhythmia. Microelectrode recordings from rat and guinea pig single isolated ventricular myocytes exposed to CO releasing molecule CORM-2 and excited at 0.2/s show repolarisation changes that develop over hundreds of seconds: action potential prolongation by delayed repolarisation, EADs, multiple EADs and oscillations around the plateau, leading to irreversible repolarisation failure. The measured direct effects of CO on currents in these cells, and ion channels expressed in mammalian systems showed an increase in prolonged late Na+, and a decrease in the maximal T- and L-type Ca++. peak and late Na+, ultra-rapid delayed, delayed rectifier, and the inward rectifier K+ currents. Incorporation of these CO induced changes in maximal currents in ventricular cell models; (Gattoni et al., J. Physiol., 2016, 594, 4193–4224) (rat) and (Luo and Rudy, Circ. Res., 1994, 74, 1071–1096) (guinea-pig) and human endo-, mid-myo- and epi-cardial (O’Hara et al., PLoS Comput. Biol., 2011, 7, e1002061) models, by changes in maximal ionic conductance reproduces these repolarisation abnormalities. Simulations of cell populations with Gaussian distributions of maximal conductance parameters predict a CO induced increase in APD and its variability. Incorporation of these predicted CO induced conductance changes in human ventricular cell electrophysiology into ventricular tissue and wall models give changes in indices for the probability of the initiation of re-entrant arrhythmia.