Potential-time Curves Research Articles

Poly(o-anisidine) and poly(o-anisidine-co-aniline) polymers synthesized on the ZnFeNi alloy coated steel surface

Abstract ZnFeNi alloy was synthesized on the carbon steel surface in a sulfate bath using the galvanostatic method at a constant current of 1.5 mA for 300 seconds. Poly(o-anisidine) homopolymer and poly(o-anisidine-co-aniline) copolymer were synthesized on the ZnFeNi coated electrode surface. Poly(o-anisidine) homopolymer was synthesized in 0.05 M o-anisidine+0.2 M sodium oxalate medium, and poly(o-anisidine-co-aniline) copolymer was synthesized in 0.05 M o-anisidine+0.05 M aniline+0.2 M sodium oxalate medium. Electrochemical synthesis was carried out by cyclic voltammetry technique. The synthesized materials were characterized by electrochemical impedance spectroscopy, linear sweep voltammetry, open circuit potential-time and anodic polarization curves. Open circuit potential-time curves showed that polymer coatings had higher open circuit potential. By linear sweep voltammetry measurements, it was determined that ZnFeNi alloys were present at the base of the polymer layers after polymer synthesis. It was understood from the anodic polarization curves that the polymer coated electrodes had lower current values ​​than the uncoated ZnFeNi coated electrode, and the poly(o-anisidine) coated electrode had lower current values ​​than the poly(o-anisidine-co-aniline) coated electrode. From electrochemical impedance spectroscopy measurements, it was determined that the polarization resistance of polymer-coated electrodes was higher than the polymer-free electrode during long periods of waiting in 3.5% corrosive solution. Among the polymer-coated electrodes, it was understood that the homopolymer poly(o-anisidine) showed better corrosion performance than the poly(o-anisidine-co-aniline) copolymer.

Selective pseudocapacitive immobilization of REE elements on carbon based electrodes

Current extraction technologies for rare earth elements at ambient conditions are reagent and energy intensive, giving rise to significant quantities of secondary waste streams. Exploration of the removal of common cations from aqueous streams has been undertaken with carbon materials and have shown promising results. However, those promising materials have not been explored extensively for rare earth element capture from aqueous process streams. In this study, a carbon electrode was investigated for the adsorption and immobilization of REE elements from aqueous solutions. Cyclic voltammetry studies of the carbon electrode displayed a pseudocapacitive behavior where it was verified that cation adsorption is accompanied by an electron transfer process. Preliminary tests showed that a current density of 89.1 mA. g−1, allowed for the pseudocapacitive adsorption (PSA) of Nd3+ cation without the formation of rare earth hydroxides. Hence, the selective PSA of Nd3+ was verified in an electrolyte solution with equimolar concentrations of Nd3+, Mg2+, Li+, Na+ and K+, achieving separation factors of 8.6, 1.1, and 10.9 for Nd3+/Li+, Nd3+/Na+, and Nd3+/Mg2+, respectively. Analysis of the potential-time curves for the various cations suggests that storage of ions in the electrode involved pore-spacings rather than interlayer spacings and was corroborated by XRD analysis. Specific capacitance as high as >640 F.g−1 for Nd3+ was also observed for the carbon electrode, with Faradaic efficiencies (FE) of >20 % for Nd3+ and Mg2+, and >9 % for Na+. Furthermore, adsorption capacity of >125 mg g−1 after 4hrs of electrosorption was observed for Nd3+. In the presence of the Nd3+ electrolyte, the electrode achieved increasing storage of Nd3+ with >94 % retention of Nd3+ with a FE > 20 % over 6 cycles between loading and releases in 1 M KCl solution. These preliminary results provide information and some guidance on the selective recovery of rare earth elements, such as Nd, in aqueous streams in the presence of competitive cations employing the use of carbon-based materials.

Electrochemical Investigation of Chloride Ion-Induced Breakdown of Passive Film on P110 Casing Steel Surface in Simulated Pore Solution: Behavior and Critical Value Determination

In the petroleum industry, the casing steel is fixed with a cement sheath to ensure reliable service in demanding conditions characterized by high temperature, high pressure, and exposure to multiple types of media. After the hydration of the cement, a porous material is produced with a highly alkaline solution filling the pores, commonly referred to as the pore solution. The casing will form a protective passive film when in contact with a highly alkaline pore solution. Nevertheless, once the cement sheath cracks, chloride ions in the stratum will pass through the cement sheath to the surface of the casing. When chloride ions accumulate to a certain concentration, the passive film will be destroyed, without exerting a protective influence on the substrate. After chloride ions come into direct contact with the casing, the casing is prone to severe failure due to corrosion perforation. The casing failure can cause a blowout outside the casing and even scrapping of the oil well. Controlling casing corrosion and ensuring casing integrity relies on understanding the critical chloride ion concentration that can cause the degradation of the passive film. Therefore, to assess the electrochemical properties and analyze the damage process of the passive film under varying chloride ion concentrations, several characterization techniques were employed. These included potential–time curves (E-t), polarization curves, electrochemical impedance spectroscopy (EIS), and Mott–Schottky curves. In addition, the composition of the passive film on the surface of the P110 casing steel was qualitatively analyzed using X-ray photoelectron spectroscopy (XPS). To further understand the surface morphology of the P110 casing steel, scanning electron microscopy (SEM) was used.

Corrosion inhibition performance of an environmentally friendly water-based nano-inhibitor

Metal corrosion not only causes huge economic losses, but sometimes even endangers personal safety. Therefore, the requirements for the corrosion resistance of metals are becoming a significant problem. The use of inhibitor is still one of the most common and effective methods to prevent metal corrosion. An environmentally friendly water-based nano-inhibitor containing nano TiO2 was prepared in this work. The open-circuit potential-time curve revealed that the voltage stability value of the steel coated with the proposed inhibitor is −0.51 V, which is higher than −0.54 V of the blank steel plate and commercial inhibitor (-0.52 V), indicating that the proposed nano-inhibitor can improve the stability of the entire system. According to the Tafel polarization curve, the inhibitor coating can significantly increase the corrosion potential, and at the same time reduces the corrosion current density. The EIS plots show that the proposed inhibitor can increase the charge transfer resistance.

Effect of Substrates Performance on the Microstructure and Properties of Phosphate Chemical Conversion Coatings on Metal Surfaces.

Phosphate chemical conversion (PCC) technology has attracted extensive attention for its ability to regulate the surface properties of biomedical metals. However, titanium (Ti)-based alloys exhibit inertia because of the native passive layer, whereas zinc (Zn)-based alloys show high activity in acidic PCC solutions. The substrate performance affects the chemical reaction in the phosphating solution, which further leads to diversity in coating properties. In this work, the zinc-phosphate (ZnP) coatings are prepared on Ti alloy (TA) and Zn alloy (ZA) substrates using the PCC method, respectively. The coatings prepared herein are detected by a scanning electron microscope (SEM), X-ray diffractometer (XRD), laser scanning confocal microscope (LSCM), universal testing machine, contact angle goniometer, and electrochemical workstation system. The results show that the substrate performance has little effect on the phase composition but can significantly affect the crystal microstructure, thickness, and bonding strength of the coatings. In addition, the ZnP coatings improve the surface roughness of the substrates and show good hydrophilicity and electrochemical corrosion resistance. The formation mechanism of the ZnP coating is revealed using potential-time curves, indicating that the metal–solution interfacial reaction plays a dominant role in the deposition process.

Modeling ‘dry’ OCP measurements to characterize archaeological iron corrosion I: Long-time transients

A series of theoretical models to describe “dry” open circuit potential measurements aimed to monitor the corrosion state of archaeological iron objects is described. The models satisfactorily describe exponential transient responses presumably driven by contact potential difference between conducting and semiconducting regions of the dense product layer. The transients are associated to double-layer and space-charge charging processes in the humidity layer covering/impregnating corrosion layers. Using reasonable equivalent circuits, theoretical models permit to describe experimental potential-time curves recorded for a set of archaeological objects.

Dynamic structures and electrochemical behavior during the formation of trivalent chromium-based conversion coating on Zn

The growth processes of trivalent chromium-based conversion (TCC) coatings on galvanized steel at room temperature (298.15 K) were studied using the potential-time curve, polarization curves, electrochemical impedance spectroscopy and scanning electron microscopy. Results display the integrity of bi-layers at stage II around 50 s causes enhanced corrosion resistance and film compactness. The protection of surficial film, dominated by inner Cr(III)-rich barrier layer, is weakened after stage III, where it presents defective bi-layers with the mixed kinetic-diffusion control. Thermodynamic stability, layer growth and structural evolution of the film formation above Zn are discussed by the Pourbaix diagrams, molecular dynamics and schematic models, respectively.

Effect of pH on the Corrosion and Repassivation Behavior of TA2 in Simulated Seawater.

The effect of pH on the corrosion and repassivation behavior of TA2 in simulated seawater was studied using electrochemical tests, immersion experiments, and surface morphology topology analysis. The results show that Ecorr and Rf increased while ipass and weight loss rate decreased as the pH of simulated seawater increased. The TA2 passive film was determined to be mainly composed of a large amount of TiO2 and a small amount of TiO. The repassivation function of TA2 can be expressed as E = −0.1375 + 0.0532ln(t − 1.241) for a simulated seawater pH of 8.2. The parameter b, which represents the slope of the potential–time curve during the friction electrode test, was used to evaluate the repassivation behavior of TA2. The increase in pH value was observed to promote the repassivation speed of the passive film, which is beneficial to the corrosion resistance of TA2.

Chronopotentiometric method for assessing antioxidant activity: A reagentless measuring technique

A simple chronopotentiometric method designed for the estimation of the antioxidant activity of liquid samples was investigated. A carbon electrode with a thin immobilized redox mediator layer on its surface was used for detection. A two-step measuring protocol was used. Firstly, in a short potential-controlled step, the mediator was set to its oxidized state; then, in the second step, the electrode potential–time curve was recorded in open circuit mode. The initial slope of this curve served as the analytical signal. It is clear that a higher antioxidant concentration produced a higher slope. The performance of adsorbed and electropolymerized Meldola Blue redox mediator layers formed on glassy carbon electrodes was investigated and compared. L-ascorbic acid was used as a sample antioxidant in this study.

Effects of NiSO4 Concentration on the Coloring Performance and Corrosion Resistance of the Colored Film on 304 Stainless Steel

The colored films were successfully prepared on the 304 stainless steel surfaces in coloring solutions with different NiSO4 contents. The purpose of this study was to investigate the effects of NiSO4 in the coloring solution on the coloring performance of 304 stainless steel and corrosion resistance of the obtained colored film in NaCl solution. The coloring rate was determined from coloring potential-time curve, and the protection properties of the color films in a 3.5% NaCl solution were characterized by potentiodynamic polarization scan, electrochemical impedance spectroscopy, and wear resistance test. The results showed that adding NiSO4 could accelerate the coloring process but brought about a negative impact on the surface’s corrosion resistance.

Preparation and properties of the anodized film on Fe-Cr-Al alloy surface

PurposeThis paper aims to find a way to improve the surface insulation, corrosion resistance and mechanical properties of Fe-Cr-Al electrothermal alloy, exploring the best oxidation condition and analyzing the oxidation mechanism.Design/methodology/approachElectrochemical workstation was used for anodic oxidation, and the effect of current density, ethylene glycol concentration and oxidation time on properties of the film were investigated by resistivity test, scanning electron microscope, electrochemical tests (potentiodynamic polarization and electrochemical impedance spectroscopy) and mechanical tests, and the oxidation process was analyzed by X-ray photoelectron spectroscopy (XPS).FindingsAccording to the potential-time curves of anodic oxidation and the analysis of XPS, the whole oxidation process can be divided into four stages. When the current density is 0.8 A/dm2, the ethylene glycol concentration is 10%, and the oxidation time is 60 min, the film has the best corrosion protection, mechanical properties and surface morphology. The resistivity of the samples is about 13 orders magnitude than that of the matrix.Originality/valueIn this paper, a protective electrically insulating film was prepared by anodic oxidation in an alkaline electrolyte solution. The oxidation conditions were optimized and the oxidation mechanism was analyzed.

Corrosion response of zinc phosphate conversion coating on steel fibers for concrete applications

In the present study, a zinc phosphate conversion coating was successfully deposited onto steel fiber surface to improve the corrosion resistance of steel fiber reinforced concrete. An understanding of phosphating temperature–coating properties was established through potentiodynamic polarization curves and electrochemical impedance spectroscopy analysis, in conjunction with scanning electron microscope (SEM) and X-ray diffraction (XRD). The results showed that increasing the phosphating temperature could promote the formation of coating, the best bath efficiency and corrosion behavior was observed at 75 °C. Also, the potential-time curves during phosphate treatment were used to elucidate the mechanism of film formation, and indicated that higher temperatures minimized the time of film formation. But at higher phosphating temperature (85 °C) was detrimental in causing matrix corrosion and grain growth. This lead to increase of porosity and decrease of corrosion resistance. Furthermore, the corrosion behavior, interface properties and bending toughness of zinc phosphate coated steel fiber-reinforced concrete in 3.5% NaCl solution was investigated and compared with general steel fiber concrete.

Influence of histidine as an electrolyte additive on the electrochemical performance of Al electrodes in 4.0 M KOH electrolyte

AbstractIn this study, the influence of histidine as an electrolyte additive on the electrochemical performance of Al electrodes in 4.0 M KOH electrolyte is studied by measuring open‐circuit potential–time curves, potentiodynamic polarization, potentiostatic oxidation, and electrochemical impedance spectroscopy. The surface morphology of Al electrodes is characterized by scanning electron microscopy. The results show that the battery performance is significantly improved by adding histidine. Samples with 50 mM histidine exhibit the highest corrosion resistance and discharging current density among all the specimens, with the corrosion current density (Icorr) being 7.471 mA/cm2 and corrosion inhibition efficiency (η) being 43.33%.

Electrochemical effects of pH value on the corrosion inhibition and microstructure of cerium doped trivalent chromium conversion coating on Zn

Abstract The electrochemical effects of cerium doped trivalent chromium conversion (TCC) coating on Zn were studied at normal temperature with potential-time curve, polarization curve, impedance spectroscopy, scanning electron microscope and energy dispersive spectroscopy. The results show protection of TCC coating increases, subsequently decreases by raising pH values. The interface of TCC coating/Zn substrate within pH 1.5–2.0 existing with metastable oxides reacts as diffusion-electrochemical mixed control, the TCC coating into pH 2.2 exists with dominated stable Cr-rich layer, then the formation rate of coating after pH 2.5 decreases. The corrosion mechanism was discussed from oxide stability in potential-pH diagrams and structural models.

Reducing the energy consumption and cell sludge of the zinc electrowinning process by using a pyramid-shaped 3D-Pb anode

In this work, the surface morphology, inner structure and phase composition of the oxide layers formed on Pb and pyramid-shaped 3D-Pb (Pyra-Pb) anodes after different periods of galvanostatic polarization were investigated. The results showed that in the preliminary stage, the lead compounds and MnO2 deposited at a higher rate on the Pyra-Pb anode. The deposited MnO2 layer on the Pyra-Pb anode was compact and well adhered, while that on the Pb anode exhibited a loose and porous structure. After a longer period of galvanostatic polarization, the oxide layer on the Pyra-Pb anode exhibited a higher stability due to its smaller thickness, denser surface structure and higher physical stability of the inner MnO2 layer. Consequently, the potential-time curve of the Pyra-Pb anode was smooth, while that of the Pb anode presented an oscillatory character with potential spikes and steps. Furthermore, the performance of the Pyra-Pb anode during 72 h of galvanostatic electrolysis was evaluated and compared with that of the Pb anode. The results showed that in the presence of 4 and 6 g L−1 Mn2+, the average anodic potentials of the Pyra-Pb anode were approximately 70 mV and 100 mV lower than those of the Pb anode, respectively. The lower potentials could be explained by the lower ohmic resistance of the MnO2 layer due to its denser structure and smaller thickness. It was also found that the Pyra-Pb anode significantly reduced the mass of the cell sludge, which could be attributed to the higher stability of the MnO2 layer and lower Mn3+ concentration in the electrolyte. In summary, it was demonstrated that the Pyra-Pb anode has a great potential to reduce the energy consumption and cell sludge of the zinc electrowinning process.

Dependence of Inhibition Effects of Oxalate, Tungstate, Molybdate and Phosphate on Purity of Zinc Metal

The inhibition effects of oxalate, tungstate, molybdate and phosphate on corrosion of 99.99 %, 99.999 % zinc and 99.95 % molybdenum metals were investigated in NaCl solutions by potential-time, AC-impedance spectra and current-potential curves. The corrosion rates of metals are highly dependent on the purity of its. The inhibition effect of these anions on 99.999 % purity zinc is less than the effect on 99.99 % purity zinc. This implies that alloying elements are effective on inhibiting efficiencies of these anions. Inhibition effect of these anions decreases also with increasing NaCl concentration. None of the studied anions behaved as inhibitors on 99.999 % purity zinc in 1 M NaCl solution. The corrosion mechanism on the zinc metals is charge-transfer, but reaction on the molybdenium is diffusion controlled in the studied solutions. Keywords : Zinc, corrosion, oxalate, tungstate, molybdate, phosphate DOI : 10.7176/JSTR/5-4-12

Galvanostatically Deposited Nickel Nanoparticles As Electrocatalyst for the Methanol Oxidation Reaction: Role of Deposition Current Density on Catalytic Activity

Alkaline direct alcohol fuel cells (ADAFCs) have high volumetric energy density, are easy to handle, store, transport and use non-noble metals as catalysts [1]. Nickel based materials are catalyst activity for alcohol oxidation [2, 3] since they present a high surface area and improved intrinsic catalytic properties [4]. Traditionally, electrodeposition of nanoparticles is carried out under potentiostatic control [5]. In contrast, Videa et al. [6] showed that galvanostatic control leads to smaller particles and narrower size distributions. This work investigates the catalytic activity of galvansotatically deposited nickel nanoparticles towards methanol electro-oxidation in alkaline media. A gold working electrode was cycled in 50 mM H2SO4. To electrodeposit nickel nanoparticles, a two second galvanostatic pulse was applied in a bath containing 50 mM NiSO4 and 500 mM NaCl as support electrolyte. Figure1a shows the transients of the electrode potential during the application of pulses with different current density. After an initial drop, a minimum value of −1.35 V vs. Hg|Hg2SO4 (MMSE) was reached; it then stabilized around −1.2 V vs. MMSE. Experiments performed with current densities higher than 4.0 mAcm-2 showed a second potential drop, reaching −1.8 V vs. MMSE. Each stage represents a different electrochemical process, complying with the current demanded by the galvanostat. Under potentiostatic conditions, electrodeposition of nickel on gold at low overpotentials occurs in a monolayer growth regime, while at higher overpotentials follows a multilayer growth [7], explaining the profile of the potential-time curves; once nickel covers the gold surface, the potential drops to allow nickel on nickel nucleation and growth. The deposits were activated by cycling in 1 M KOH, to generate a NiOOH layer. In the typical activation voltammogram shown in Figure1b, the redox peaks Iaf and Icb correspond to the formation of NiOOH from the following redox process: Ni(OH)2 + OH- ==> NiOOH + H2O + e- After activation the electrode was cycled in 1 M KOH + 0.5 M methanol. The voltammogram (Figure1c) exhibited two additional anodic peaks, IIaf and IIab, corresponding to the oxidation of methanol on fresh NiOOH and NiOOH reactivated by desorption of poisonous species [8]. Following Chen et al. [9] the surface concentration of NiOOH was estimated from the charge under peak Iaf. The electrocatalytic intensity was calculated adding the current of peaks IIaf and IIab. This parameter, introduced by Ding et al. [10], quantifies the electrocatalytic ability of the material. Figure1d depicts the dependence of the surface NiOOH concentration (Γ) and EI on the applied current density. The maximum value for Γ was achieved at 2.2 mAcm-2. Taking into account that current efficiency increases at lower overpotentials [7], the deposited nickel should increase as the applied current increases. Therefore, it is reasonable to infer that the surface area obtained has is the largest. On the other hand, the deposit obtained at 8.8 mAcm-2 reached the highest EI value, implying particles intrinsically more active than those obtained at 2.2 mAcm-2. The material deposited in the monolayer regime has larger surface area but is less active than the nickel multilayer deposit. All nickel nanostructured deposits obtained by galvanostatic electrodeposition showed good electrocatalytic activity towards methanol electro-oxidation, comparable to the results obtained by more complex deposition methods [3,9]. Figure 1. a) Potential transients during galvanostatic deposition of Ni (50 mM NiSO4 + 500mM NaCl) b) Cyclic Voltammogram of Ni deposit in 1 M KOH at 50 mVs-1. c) Cyclic Voltammogram of Ni deposit in 0.5 M Methanol in 1 M KOH at 50 mVs-1. d) Dependence of surface NiOOH concentration (Γ) and electrocatalytic intensity (EI) on the current deposition. References I. Ozoemena, RSC Adv., 6, 89523 (2016).Fleischmann, K. Korinek and D. Pletcher, J.Electroanal. Chem. Interfacial Electrochem. 31, 39 (1971).Wang, Q. Zhao, H. Hou, Y. Wu, W. Yu, X. Ji, L. Shao, RSC Adv., 7, 14152 (2017).B. Raoof, R. Ojani, S. R. Hosseini, S. Afr. J. Chem., 66, 47 (2013).Ustarroz, X. Ke, A. Hubin, S. Bals, H. Terryn J. Phys. Chem. C 116, 2322 (2012).T. Martínez, G. Zavala, and M. Videa, J. Mex. Chem. Soc., 53, 7 (2009).Lachenwitzer, O. M. Magnussen, J. Phys. Chem. B 104, 7424 (2000).Danaee, M. Jafariana, F. Forouzandeh, F. Gobal, M.G. Mahjani, Int. J. Hydrog. Energy, 33, 4369 (2008).Chen, S. D. Minteer, J. Power Sources, 284, 27 (2015).Ding, Y. Zhao, L. Liu, Y. Cao, Q. Wang, H. Gu, X. Yan, Z. Guo, Int. J. Hydrog. Energy, 39, 17622 (2014). Figure 1

Controlled Electrodeposition of Zinc Oxide on Conductive Meshes and Foams Enabling Its Use as Secondary Anode

Both compact and porous zinc oxide (ZnO) films were electrochemically deposited out of aqueous zinc nitrate solutions under pulsed galvanostatic control onto different three-dimensional (3D) substrates. Gold and carbon meshes as well as copper and nickel foams were used as substrates, all having complex geometries in micrometer dimensions with high surface area. Electrodepositions of ZnO were controlled by regulating the most relevant parameters: the applied current density, the total deposition time, and the length of current pulses and pauses to avoid gas evolution interfering with film growth at the electrodes. Optimization of these parameters for each of the substrates allowed deposition of homogeneous ZnO films of the desired total film thickness. Potential-time curves measured during deposition helped to monitor film growth. Scanning electron microscopy (SEM) micrographs showed that pinhole-free ZnO films were deposited uniformly in a 3D manner on all substrates. X-ray diffraction (XRD) measurements confirmed the formation of highly crystalline ZnO films. Such electrodeposited ZnO films on electronic conductive substrates with high surface area are promising for application in energy storage and conversion systems – especially for secondary batteries with zinc anodes which was shown by cyclic voltammetry (CV).

Corrosion Protection of Stainless Steel by Poly(Carbazole-co-pyrrole) Films Deposited on TiO2 Sol–Gel Film

ABSTRACTThe poly(carbazole-co-pyrrole) copolymer was synthesized on TiO2 sol–gel precoated 304 stainless steel (TiO2) by cyclic voltammetry in tetrabutylammonium perchlorate containing acetonitrile solution. The synthesized coating was characterized by attenuated total reflectance–Fourier transform infrared spectroscopy, scanning electron microscopy, and solid-state conductivity measurements. Corrosion protection behavior of the TiO2/poly(carbazole-co-pyrrole)-coated steel was evaluated by open circuit potential–time curves, potentiodynamic polarization, and electrochemical impedance spectroscopy methods. Corrosion test results showed that TiO2/poly(carbazole-co-pyrrole) composite film enhanced corrosion resistance of stainless steel up to 50 days of immersion in 0.1M HCl corrosive medium.

Dynamics of a Blended Lithium-Ion Battery Electrode During Galvanostatic Intermittent Titration Technique

A multi-particle model is developed and applied to the data from galvanostatic intermittent titration technique (GITT) experiments with varying pulse currents and relaxation periods on a LiNi1/3Mn1/3Co1/3O2 −LiMn2O4 (NMC-LMO) blended lithium-ion electrode. The good agreement between the simulated and experimental potential-time curves shows that the model is applicable for all GITT conditions considered, but more accurate for the case of small current pulse discharges with long relaxation times. Analysis of the current contribution and the solid-state surface concentration of each active component in the blended electrode shows a dynamic lithiation/delithiation interaction between the two components and between micron and submicron NMC particles during the relaxation periods in the GITT experiments. The interaction is attributed to the difference in the equilibrium potentials of the two components at any given stoichiometry which redistributes the lithium among LMO and NMC particles until a common equilibrium potential is reached.