Electrochem

Formazanates are the mono-deprotonated form of formazans, which exhibit a notable property of noninnocent behavior. Here, a new nickel–formazanate complex, [Ni(3-cyano-1,5-mesitylformazanate)((2-mercaptopyridinate)-κN,S)], was synthesized and characterized via NMR spectroscopy, crystallography, and elemental analysis. Cyclic voltammetry using water as the proton source revealed the catalytic activity of the complex for electrochemical hydrogen production. Further study with acetic acid as a proton source estimated an overpotential of 0.73–0.79 V, current efficiency of 82.1%, and turnover number of 12.2 (for 2 h). The catalytic mechanism is discussed based on electrochemical data, spectral changes, and quantum calculations, concluding that the noninnocent ligand plays an important role in catalytic behavior. A side-product complex and a dinuclear derivative complex were also characterized crystallographically. Full article

Potassium-selective ionophores with high selectivity and chemical stability are essential for electrochemical sensing in clinical, biological, and environmental analysis. Here, three new silane- and disiloxane-bridged bis(15-crown-5) derivatives—two silane-bridged isomers bearing two octyl groups (1) or two 2-ethylhexyl groups (2), and a disiloxane-bridged derivative bearing four isopropyl groups (3)—were synthesized and evaluated as ionophores for poly(vinyl chloride) membrane ion-selective electrodes (ISEs). The ISEs based on 1–3 exhibited near-Nernstian responses to K⁺. Electrodes based on silane-bridged 1 and 2 showed higher K⁺ selectivity over Li⁺, Na⁺, Mg²⁺, and Ca²⁺ than the commercially available pimelate-bridged bis(benzo-15-crown-5) ionophore 4, and their selectivity was comparable to that of valinomycin for most of the metal cations examined. Notably, compound 2, bearing bulky 2-ethylhexyl groups, showed exceptional tolerance in strongly acidic media and maintained a nearly constant K⁺/Na⁺ selectivity (potentiometric selectivity coefficient, log k_K,Na ≈ −3.4) for more than 200 days under intermittent dry-storage conditions, whereas the ISE based on 4 showed a marked loss of selectivity after approximately 100 days. Disiloxane-bridged 3 also exhibited high K⁺ selectivity and acid tolerance. Overall, sterically optimized silane/disiloxane bridging units offer an effective strategy for designing durable, high-performance synthetic K⁺ ionophores. Full article

The conversion of hydrogen into electricity is a subject of intense interest. Various technologies are available at laboratory level, but in industrial applications, the most established of them is the proton exchange membrane-based fuel cell. This increased interest, combined with the maturity of the technology, has led to attempts to integrate fuel cells into hybrid systems with renewable energy sources. Such hybrid systems are subject to numerous studies, most of which are aimed at optimizing installed capacity in order to reduce the cost of energy production, of investment, etc. This article aims to provide an experiment-based approach for a simple yet accurate model linking electrical power with hydrogen consumption that can be used in the design and optimization procedures for hybrid systems. For this purpose, an experimental setup with a 1 kW fuel cell was built at the Technical University of Sofia, where experimental studies were conducted to enable the development of the model. Although the proposed model does not reflect the influence of certain technological factors on the operation of the fuel cell, it provides sufficient accuracy to determine the hydrogen consumption for a given electrical power when used in operation simulations of the hybrid system. Full article

This work reports the synthesis of the organic–inorganic copper chloride perovskite (C₆H₅CH₂NH₃)₂[CuCl₄] and its application as an electrode material for lithium-ion batteries. Hybrid copper halide perovskites have emerged as environmentally friendly alternatives to lead-based systems due to their structural versatility and chemical stability; however, their electrochemical energy storage properties remain largely unexplored. To the best of our knowledge, this is the first report investigating (C₆H₅CH₂NH₃)₂[CuCl₄] as an electrode material for lithium-ion batteries. The structural and morphological characteristics of the material were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and infrared spectroscopy (IR), confirming the formation of a layered perovskite structure. Electrochemical performance was evaluated by cyclic voltammetry and galvanostatic charge–discharge measurements. The material delivered an initial specific capacity of 114 mAh g⁻¹ at a current density of 20 mA g⁻¹ and maintained a coulombic efficiency around 99% after 100 cycles, indicating good cycling stability. The electrochemical behavior suggests that the reversible redox activity of Cu species contributes significantly to the charge storage mechanism. Postmortem XRD analysis revealed that the original perovskite framework was only partially retained after cycling, as several characteristic diffraction peaks remained while others disappeared, indicating partial structural decomposition. These results highlight the potential of chlorocuprate-based hybrid perovskites as alternative electrode materials for lithium-ion batteries. Full article

Due to their remarkable long-term stability, variable bandgap, and relatively high absorption coefficient, copper indium gallium diselenide (CIGS) solar devices are among the most promising photovoltaic technologies due to their compatibility with lightweight substrates and special applications. This review critically discusses recent progress in the electrodeposition-based fabrication of CISe/CIGSe absorber layers, with special focus on electrolyte chemistry, electrochemical deposition mechanisms, precursor composition and morphology, post-deposition selenization/sulfurization, absorber quality, and photovoltaic device performance. We discuss aqueous and non-aqueous electrolytes, one-step and sequential electrodeposition, pulse-based deposition techniques, compositional control, film quality enhancement, Cd-free buffer layers, and large-area processing. The issues arising from the varied electrochemical behaviors of Cu, In, Ga, and Se are discussed, with specific emphasis on hydrogen evolution, limited integration of Ga, development of secondary phases, inhomogeneity of precursors, and process reproducibility. We review recent progress in device performance and explain typical manufacturing methods, and we summarise the key criteria for scaled electrodeposition. This review therefore sets up an integrated processing–structure–performance perspective for the further development of efficient and industrially relevant electrodeposited CIGSe solar cells. Full article

Additive manufacturing provides a fabrication route for electrode components with controlled macrostructure; however, printable carbon inks that also incorporate oxygen reduction reaction active precursors remain underdeveloped. Here, XC-72 carbon was combined with selected metal precursors to prepare N–C, Fe–N–C, and Pt-containing carbon ink formulations for direct ink writing. The precursor mixtures were incorporated into a polyurethane-based matrix, pyrolyzed at 900 °C, and characterized using X-ray diffraction, oscillatory rheology, rotating ring-disk electrode measurements, Brunauer–Emmett–Teller surface-area analysis, and scanning electron microscopy. XRD confirmed retention of carbon diffraction features and the formation of metal-containing crystalline phases after pyrolysis. Oscillatory rheology showed storage moduli exceeding loss moduli for the tested formulations, indicating elastic-dominant behavior suitable for shape retention during printing. For the PGM-free formulations, incorporation of nitrogen and iron precursors improved ORR onset potential, half-wave potential, limiting current density, and electron-transfer selectivity relative to the carbon control. BET analysis showed a decrease in accessible surface area after precursor incorporation, consistent with partial pore blocking or structural modification during pyrolysis. These results establish a printable formulation platform for ORR-active carbon-based inks, while future work is required to isolate the effects of printed architecture, pore hierarchy, and durability under fuel-cell operating conditions. Full article

Photoelectrochemical (PEC) energy conversion is a promising approach for solar-to-chemical fuel production, but its practical performance is limited by insufficient visible-light utilization and charge-carrier recombination. Here, poly(3,4-ethylenedioxythiophene) (PEDOT)-centered TiO₂ hybrid electrodes were prepared by electropolymerizing PEDOT on FTO substrates, followed by electrochemical doping/dedoping treatment and coating with commercial TiO₂ as a model oxide semiconductor. SEM, EDS, and LIBS analyses confirmed the successful deposition of TiO₂ onto PEDOT-based films. Four-probe measurements showed that electrochemical doping reduced the apparent resistance of PEDOT-based electrodes, while UV–vis spectroscopy revealed enhanced long-wavelength absorption for doped PEDOT-containing films. PEC measurements using TiO₂, PEDOT, and TiO₂–PEDOT electrodes showed that PEDOT-containing electrodes exhibited much stronger photoresponses than commercial TiO₂ alone under both HER- and OER-relevant conditions. The TiO₂–PEDOT electrode showed stable photocurrent responses under chopped illumination and retained photoresponse under illumination transmitted through a 410 nm UV-cut filter, supporting the primary role of PEDOT in visible-light utilization. Long-term chronoamperometry further showed that TiO₂–PEDOT retained approximately 99.0% of its cathodic current under HER-relevant conditions and 91.9% of its anodic current under OER-relevant conditions after 5200 s of continuous illumination. The improved response of TiO₂–PEDOT compared with PEDOT alone suggests that TiO₂/PEDOT physical contact may assist interfacial charge separation and transport. These findings demonstrate that PEDOT-centered metal oxide/conducting polymer hybrids provide a useful model platform for visible-light-responsive PEC energy-conversion applications. Full article

An Ag|AgCl redox couple has been thought to work as a reversible reference electrode, although metal dissolution often occurs irreversibly. This report examines the kinetics by means of ac-impedance of AgCl films at the Ag electrode. A brief result is that the reaction rate for conventional voltammetric currents is totally irreversible, although it can be enhanced with the thickness of the AgCl film. According to the frequency-dependence of the imaginary admittance, the double layer capacitance is determined only by the geometrical area of the Ag-electrode to exhibit 140 μF cm⁻². This value is caused by the delocalized charge of AgCl dipoles rather than by water dipoles. The charge transfer rate of AgCl + e⁻ ↔ Ag + Cl⁻ was evaluated from the variation in the real admittance with the frequency to yield the charge transfer rate constant on the order of 10⁻⁹ cm s⁻¹. The rate constants increased with the surface density (Γ) of the deposited AgCl in proportion to Γ^0.3. The fractional power of the increase indicates that the reaction should occur not only at the geometrical area of the Ag-electrode but also at fluctuated Ag-particles in electric connection with the Ag-electrode, caused by percolation. The reversibility of Ag|AgCl can be realized at current densities smaller than 0.1 μA mm⁻², exemplified by 10 nA at a 0.3 mm disk. Then, Ag|AgCl can be used as a counter electrode in ultramicroelectrode techniques in a two-electrode system. Full article

Anthracycline agents, principally doxorubicin and daunorubicin, are widely used in oncology yet carry a narrow therapeutic index and pronounced interindividual pharmacokinetic variability that exposes patients simultaneously to the risk of subtherapeutic dosing and cumulative cardiotoxicity. Conventional therapeutic drug monitoring (TDM) based on periodic venous sampling and offline high-performance liquid chromatography cannot resolve the sub-minute concentration dynamics that determine organ-specific drug exposure. Electrochemical aptamer-based (EAB) sensors couple nucleic-acid aptamers, self-assembled monolayers, and methylene blue redox reporters on gold microelectrodes to convert binding-induced conformational changes into real-time, reagent-free electrochemical signals. Recent advances in this field fall into five areas: signal interrogation strategies, from kinetic differential measurement to calibration-free Fourier-transform impedance spectroscopy (FFT-EIS); interface engineering including nanostructured electrodes and AI-guided aptamer design; in vivo multi-compartment pharmacokinetic monitoring and closed-loop feedback drug delivery; the mechanisms of in vivo signal drift alongside antifouling countermeasures spanning hydrogel barriers, zwitterionic brushes, and xenonucleic acid backbone substitution; and FDA premarket pathways and clinical translation, including Premarket Approval requirements and the emerging Real-Time Clinical Trial (RTCT) framework. In live rodents, dual-compartment monitoring has resolved a reproducible 30–60 min plasma-to-ISF lag for doxorubicin at 12 s temporal resolution; calibration-free FFT-EIS interrogation achieves inter-animal coefficients of variation below 12% without individual pre-calibration; and xenonucleic acid backbone substitution has extended continuous in vivo operation to seven consecutive days. Unlike prior EAB reviews that survey general molecular targets or benchtop aptasensors, this review uniquely integrates anthracycline-specific in vivo pharmacokinetics, multi-compartment plasma–ISF monitoring, calibration-free interrogation, XNA-enabled long-term stability, and FDA/RTCT regulatory translation into a single clinical roadmap. Three gaps still separate rodent proof-of-concept work from chemotherapy patients: clinical-context validation, tumor microenvironment calibration, and anthracycline-specific XNA aptamer design. Full article

The dynamics and transient response of fuel cell systems are critical aspects, especially in commercial applications where an immediate response to fluctuating power demands is required. This study presents experimental results obtained from evaluating the dynamic behavior of a 1.2 kW Ballard Nexa fuel cell, subjected to various operational disturbances, including startups, shutdowns, step load increases, irregular and constant loading, and system purging operations. The variables analyzed include voltage, current, and temperature, both in individual cells and in the entire system. The results indicate that the temperature exhibits an attenuated response with an arc-like evolution, but with an upward trend correlated with the increase in the demanded current. Meanwhile, when multiple load steps are applied, the system exhibits rapid responses in both cell and stack voltages, with transient overshoot and undershoot peaks whose magnitudes increase proportionally with the applied current. Regarding the purge system, tests show that its activation improves operational efficiency, resulting in approximately 0.3 V of voltage increase per operation. Furthermore, it is observed that the purge frequency increases with higher external load levels, suggesting a direct interaction between energy demand and active waste gas management in the system. Full article

High lithium and manganese oxides (HLMs), also known as lithium- and manganese-rich oxides (LMR), are an alternative to the state-of-the-art (SoA) cathode materials for Li-ion battery cells due to their high specific capacity, working potential, and potential elimination of cobalt from their composition. Nevertheless, they are claimed to undergo accelerated capacity and potential fade. In this work, an extensive electrochemical characterization is conducted while revisiting the most relevant literature on HLM. The classical galvanostatic cycling is used to conduct differential voltage and incremental capacity analyses, while impedance spectroscopy and galvanostatic intermittent titration techniques are applied to complement this test. The results are complemented with online electrochemical mass spectrometry and postmortem characterization. Loss of anode active material is identified as the main degradation mechanism, aggravated by potential slippage. Moreover, the hypotheses on degradation mechanisms are further confirmed by changing the voltage cutoffs of the cells, limiting the Li₂MnO₃ activation. The results are benchmarked with SoA LiNi_0.8Mn_0.1Co_0.1O₂-based cells with a promising balance for HLM in some cases. This work serves as a guide to assist in the interpretation (and avoid misinterpretation) of the results with Li-ion batteries consisting of HLM electrodes. Full article

Paracetamol (PA) ranks among the most frequently prescribed over-the-counter analgesic and antipyretic agents worldwide; nonetheless, overdose scenarios are associated with severe hepatotoxic and nephrotoxic consequences, while its incomplete metabolic removal renders it a persistent micropollutant in surface and wastewater systems. These concerns underscore the urgent need for rapid, cost-efficient, and highly sensitive analytical tools capable of quantifying PA at trace levels in complex matrices. In the present study, spherical gold nanoparticles (AuNPs) were fabricated through an environmentally benign route exploiting an aqueous extract of Juniperus sp. leaves as the reducing and capping agent, with polyvinylpyrrolidone (PVP) serving as an additional colloidal stabilizer. The resulting nanoparticles were immobilized on a glassy carbon electrode to construct an AuNPs/PVP/GCE sensing platform. Physicochemical characterization by UV–Vis spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM) verified the spherical morphology, narrow size distribution, and colloidal stability of the synthesized AuNPs, and further confirmed a 3.5-fold enlargement of the electroactive surface area relative to the unmodified electrode. Under fully optimized conditions, the fabricated sensor delivered a well-defined linear voltammetric response toward PA oxidation across the concentration interval of 0.05–0.31 µM (R² = 0.9939), with a limit of detection of 0.024 µM and a limit of quantification of 0.080 µM. The sensor retained its analytical accuracy in the presence of common co-existing species, including ascorbic acid, uric acid, dopamine, caffeine, ibuprofen, and adrenaline. Quantitative determination of PA in commercial tablet formulations via the standard addition approach yielded results in close agreement with the declared content, confirming the practical suitability of the AuNPs/PVP/GCE platform for routine pharmaceutical quality control. Full article

The morphological and structural state of rough solid electrodes usually has a complex effect on the kinetics of an electrochemical process. In order to correctly distinguish the influence of different factors on the rate of an electrode reaction, it is necessary to first separate a purely geometric current rise caused by the surface area increase. At the same time, it is necessary to take into account that surface roughness itself often not only leads to a geometric rise in the electrode area, but also contributes to a change in the kinetic parameters of the electrochemical process. As a consequence, the conclusion regarding an electrocatalytic effect will be reasonable only if the roughness effect is correctly taken into account. The most difficult problem is to establish the role of roughness when experimental electrochemical data are obtained under mixed diffusion–kinetic control of the electrode process. However, the use of appropriate theoretical approaches is required to correctly determine the kinetic characteristics of the electrochemical stage, i.e., of the charge transfer stage. This paper establishes the influence of the morphology and structure of electrodeposited copper coatings on the kinetics of the cathodic reduction of nitrate ion, which occurs in a mixed diffusion–kinetic mode, using the theoretical model of chronoamperometry of an electrochemical process on a rough electrode developed earlier by the authors. Several Cu-electrodes with roughness and structure, the parameters of which vary widely enough, were obtained by cathodic deposition from sulfate solutions of different compositions. The integral (roughness factor) and local (average roughness) characteristics of the surface morphology were determined by methods of underpotential deposition and atomic force microscopy, respectively. Structural investigation of the electrodeposited coatings was carried out by X-ray diffraction to determine their crystallographic structure and average crystallite size. The methods of voltammetry and a rotating disk electrode revealed the mixed kinetics of the electroreduction of ${\mathrm{NO}}_3^{-}$ ions. The kinetic parameters of the charge transfer stage on the copper coatings with a roughness factor of f_r ≤ 3.5 are determined for the first time in this paper by treatment of the experimental current decay curves with the non-linear theoretical equation obtained by the authors for the chronoamperogram of the process on rough electrodes. It was found that the rate constant of the charge transfer stage and the exchange current density of the nitrate ion electroreduction increase by about 50%, with an increase in the average surface roughness from 25 to 120 nm. Considering that this effect is not caused by a purely geometric increase in the true surface area of the electrode, and that the average crystallite size is approximately the same (25 ± 2 nm) for all investigated coatings, it can be concluded that the electrocatalytic activity of copper increases in the reaction of the cathodic reduction of nitrate ions during the transition to copper electrodes with the higher average surface roughness. Taking into account XRD data, the role of the structural and morphological state in the kinetics of the electroreduction of nitrate ions has been established. The smoothest polycrystalline coating was found to be the least electrocatalytically active in this reaction. On the contrary, the roughest coatings with the most prominent plane (220) show the highest activity, which increases with increasing average roughness, possibly due to the growth of defects and excess energy of such curved surfaces. Full article

The development of efficient catalysts for the glycerol oxidation reaction (GOR) is crucial for advancing direct glycerol fuel cells. This study provides mechanistic insights into the glycerol electro-oxidation reaction (GOR) on Co@Pt/C, Ni@Pt/C, and Sn@Pt/C catalysts using in situ FTIR spectroscopy. While the structural and electrochemical properties of these materials have been previously reported, their reaction pathways and product selectivity under alkaline conditions remain unclear. Electrochemical performance was evaluated through cyclic voltammetry (CV) and chronoamperometry (1.0 M KOH + 1.0 M glycerol), revealing that the bimetallic catalysts exhibited superior catalytic activity compared to Pt/C. Co@Pt/C demonstrated the highest performance, with a 7.5-fold increase in current density relative to Pt/C, followed by Sn@Pt/C (3.4-fold) and Ni@Pt/C (2.8-fold). In situ FTIR analysis identified key oxidation products, including C3, C2, and C1 species, with evidence of both partial and complete oxidation. These findings demonstrate that the core metal plays a key role in governing reaction pathways and C–C bond cleavage, providing important insights for the rational design of anode materials in direct glycerol fuel cells. Full article

Direct ammonia fuel cells (DAFCs) offer a promising pathway for carbon-free energy conversion but their practical performance is limited by sluggish cathode kinetics. In this work, non-precious FeCoN catalysts offer a cost-effective solution, yet carbon support optimization is crucial for activity and stability. FeCoN/XC-72R, FeCoN/CNT, and FeCoN/CNH cathode catalysts were synthesized by annealing at 550–750 °C. Their structure and morphology were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electrochemical behavior was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in alkaline medium containing KOH and NH₄OH. FeCoN/XC-72R exhibited the lowest resistance of 27 Ω and superior activity. In single cell tests using a 40 wt% PtIr/C anode catalyst at 2 mg cm⁻², the FeCoN/XC-72R catalyst achieved the highest power density of 71 mW/cm² under optimized conditions of 0.1M NH₄OH + 3M KOH, 100 °C, and O₂ feed. Among the carbon supports, carbon black (XC-72R) proved the most effective support for FeCoN catalysts in low concentration DAFCs, outperforming carbon nanotubes (CNTs) and carbon nanohorns (CNHs). These findings highlight the importance of carbon support selection in the design of efficient cathodes for next generation low concentration direct ammonia fuel cells. Full article

Understanding lithium distribution and transport within Li-ion battery components is critical in improving battery longevity, safety and performance. This study investigates lithium concentration profiles across the interface of an aluminum-doped Li₇La₃Zr₂O₁₂ (Al-LLZO) solid electrolyte and a lithium metal anode using Nuclear Reaction Analysis (NRA), a non-destructive depth-profiling technique. The Al-LLZO electrolyte was synthesized via electrospinning, producing nanofibers, which were subsequently sintered into pellets of average thickness 380 µm. These pellets were integrated into a Li|Al-LLZO|NMC-111 half-cell and cycled at 0.1 C for 1, 3, and 10 cycles, indicating pronounced lithium accumulation at the electrolyte–anode interface. Using NRA, this study provided a clear pathway for better understanding lithium transport and interfacial behavior, by quantitatively measuring the lithium distribution at the Al-LLZO electrolyte–electrode interface, and to look at the changes at this interface over the battery cycles. Full article

Cost-effective, durable, and environmentally friendly electrocatalysts to be used for the alkaline hydrogen evolution reaction (HER) represent one of the key challenges facing green hydrogen generation. In this context, a TiO₂-doped hydrochar derived from Phoenix dactylifera L. Deglet Nour (date pits) was synthesized and incorporated into a graphite-based electrode to improve HER performance in a 1 M KOH solution. Three TiO₂ loadings (1, 3, and 6 wt%) were systematically studied and compared using electrochemical techniques to evaluate the influence of oxide incorporation on HER kinetics. In parallel, physicochemical characterization analyses were performed to acquire an in-depth understanding of the morphology, composition, and surface properties of biomass-derived carbonaceous materials and to establish correlations with their electrochemical behavior. The G/HC-3% TiO₂ electrode exhibited the most pronounced electrocatalytic performance, with an overpotential of 194 mV at −10 mA·cm⁻² and a Tafel slope of 67 mV·dec⁻¹, indicating favorable interfacial charge transfer kinetics. The present work demonstrates that biomass-derived TiO₂-doped hydrochar has significant potential as a sustainable and high-performance electrocatalyst in alkaline water electrolysis. Full article

This study proposed an effective capacitance (C_ec) for bare and conducting polymer-covered electrodes using electrochemical impedance spectroscopy (EIS). Bare electrodes show three regimes: potential-dependent Helmholtz capacitance, Gouy–Chapman–Stern diffusion capacitance (1 MHz–10 Hz), and complex low-frequency responses, deviating from semi-infinite Warburg diffusion (1 Hz–10 mHz). Polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) PEDOT-based electrodes exhibit larger potential-dependent diffusion pseudocapacitance (1 MHz–10 Hz) and the absence of a Warburg tail or a nearly horizontal low-frequency slope at 0.01–0.026 (1 Hz–10 mHz). A high-frequency C_ec of a PANI membrane correlates with bulk electrolyte concentration, while bare electrodes are less affected and dominated by Helmholtz capacitance. The equivalent circuit of the time-dependent EIS impedance spectrum for bare electrodes and PANI and PEDOT-based electrodes shows parallel capacitor behavior in combination with high-frequency capacitance (1 MHz–10 Hz) and a low-frequency response (1 Hz–10 mHz). The mathematical simulation of effective capacitance C_ec with respect to time period t (f⁻¹) follows two time constants (τ = RC), representing double-layer capacitance or pseudocapacitance (τ₁) and complex low-frequency responses or Warburg diffusion (τ₂) for bare electrodes and conducting polymer-based electrodes, respectively. This simulation analysis also elucidates the frequency dependence of the Warburg characteristic frequency (ω) and the extension of the double-layer capacitance diffuse distance L_D for H⁺ with GC electrodes to approximately 7.37–15.15 μm over a time interval of ca. 1 s (t = f⁻¹). The diffusion coefficient D_i of K⁺ ion transfer through a PEDOT solid contact from 1 mC (0.1 µm) to 10 mC (1 µm) is in the range of 0.57–12 × 10⁻¹⁰ cm²·s⁻¹, following a power law with an exponent of 1.75 with respect to the polymerization time of PEDOT, which is inconsistent with Fick’s law. Full article