Electrochemistry Communications最新文献

As electrochemical energy storage continues to gain importance, researchers have been exploring novel materials and electrode designs to enhance performance. While these innovations have significantly improved the performance of energy storage devices, the specific mechanisms responsible for their success remain unclear. One powerful tool for gaining insights into how modifications to the electrode can enhance cell performance is cyclic voltammetry (CV). However, interpreting CV data can be challenging, and simple analytical relations are often inadequate for accurate assessment. Moreover, different analytical methods can yield conflicting results, leading to confusion within the research community and hindering progress in the field. To address these challenges, our study aims to investigate the contributions of surface and diffusion-controlled processes to charge storage in supercapacitor applications. We will employ conventional methods to examine how these processes can lead to the misinterpretation of CV data and identify the advantages and limitations of different analytical approaches. Our research underscores the importance of developing models that faithfully replicate the system of interest to gain insights into charge storage mechanisms. By identifying these key factors, our findings could pave the way for the development of more efficient and effective energy storage technologies.

In this work, we have synthesized two new Schiff-bases from 2,2-dimethylpropane-1,3-diamine and n-hydroxy-n-methoxybenzaldehyde. The synthesized Schiff-bases were characterized by ¹H NMR, ¹³C NMR. The anti-corrosive property of the compounds were investigated using weight loss, polarization and EIS techniques against 1 M HCl solution. For additional support for this work, DFT studies also carried out for Schiff-bases. The surface morphology was examined by AFM and SEM to determine this inhibition mechanism. Schiff-base derivatives were found to successfully suppress steel corrosion. EIS studies showed that charge transfer resistance occurs because of the presence of an inhibitor. Moreover, increasing Schiff-bases concentration decreased the double-layer capacitance (C_dl) value because less charged species were attracted to the metal surface. Polarization measurements clearly showed that the inhibitors suppressed both anodic and cathodic reactions. In conclusion, this study demonstrates that these compounds inhibit corrosion via chemisorption of organic compounds. By studying the effects of hydroxyl groups in ortho-, para- positions, the best one as inhibitor was found to be ortho position of OH in Schiff base (i.e., 6-SH).

The rapid development of science and technology, as well as the trend toward intelligence, has resulted in a surge in the demand for excellent energy storage devices for smart devices. At present, the most widely used lithium ion batteries have limited further development because of their high cost and various disadvantages of electrolytes (flammable and toxic). In spite of the low costs and safety of aqueous zinc-ion batteries, the high radius of the zinc ions and strong electrostatic interactions make cathode materials without excellent performance difficult to find. Various oxidation states, structural diversity, excellent multiplicity performance and high capacity have attracted researchers to vanadium-based oxides in recent years. However, vanadium-based oxides have disadvantages such as poor structural stability and low electrical conductivity, so this paper summarizes the progress of research on vanadium oxide cathode materials such as V₂O₅, VO₂, V₂O₃, etc., and provides an outlook on future development directions.

NASCION-type Na₄MnV(PO₄)₃/C was synthesized through a sol–gel method. Two Na⁺ ions can reversibly (de)intercalation from/into the unit structure, with a reversible capacity of 106.7 mAh/g. The charge–discharge curves show a voltage slope at 3.4 V, and a plateau at 3.6 V. To elucidate the sodium storage mechanisms, the structure evolution and electron transfer are demonstrated using in-situ X-ray diffraction and ex-situ X-ray absorption spectroscopy. It is found that at different stage of the electrochemical process, it undergoes different phase reaction process with different redox couples. A single-phase reaction occurs when the first sodium-ion extracted from Na₄MnV(PO₄)₃ with a V³⁺/V⁴⁺ redox, while a two-phase reaction takes place when the second sodium-ion extracted with a Mn²⁺/Mn³⁺ redox. Galvanostatic intermittent titration technique, GITT, indicates the single-phase reaction process shows a faster kinetic compared to the two-phase reaction process. These findings between the kinetics, chemical and structural evolution provide new insight into the sodium storage mechanisms of NASICON-type cathode, and further the understanding of other materials for sodium-ion batteries.

Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is a promising candidate for future lithium-ion battery (LIB) electrolytes because of its increased stability and ionic conductivity. One major drawback of this salt, however, is its ability to dissolve Al, leading to a degradation of current collectors in LIBs over time. Surface passivating additives can reduce or even completely suppress the dissolution. A truly cost and material-efficient suppression, however, can only be achieved by identifying the ideal (i.e., minimal) amount of additive. Therefore, quantifying the dissolution-suppressing effect of additives is necessary to create an optimum electrolyte mixture. In this work, we examine the influence of lithium hexafluorophosphate (LiPF₆) addition to LiTFSI-based electrolytes via cyclic voltammetry (CV) in an electroanalytical flow cell (EFC) coupled on-line to an inductively coupled plasma mass spectrometer (ICP-MS) for continuous downstream elemental analysis. This setup allows the potential resolved quantification of Al dissolution with unprecedented precision in real-time. With that, we found that already very small amounts of 0.02 M LiPF₆ added to 0.98 M LiTFSI will drastically reduce the total dissolved amount of Al during one CV cycle by a factor of ∼ 20, while electrolytes containing 0.30 M LiPF₆ (and 0.70 M LiTFSI) completely suppress the dissolution of Al. These findings allow the substitution of large portions of LiPF₆, enabling the production of safer LIBs without risking current collector degradation.

This work elucidates the photoelectrochemical (PEC) sensing of melatonin employing graphene oxide nanoribbons (GONRs) synthesized through a microwave-assisted method. GONRs served as electrocatalysts for screen-printed carbon electrodes (SPCE) to facilitate melatonin detection. We incorporated both a light-emitting diode (LED) and a solar simulator as light sources for PEC evaluations. Cyclic voltammetry revealed that the faradaic currents corresponding to melatonin oxidation on GONRs-modified SPCE were amplified under both LED and simulated solar light irradiation. Notably, the GONR (150 W) registered the most pronounced enhancement in the photo-assisted faradaic current and the highest conversion efficiency. Employing the solar simulator, certain thermal factor ratios concerning conversion efficiencies surpassed 50.0% at light intensities of both 80 mW/cm² and 100 mW/cm². Conversely, with the LED source, the thermal contribution remained below 15.0% of the total PEC faradaic current. We posit that obtaining conversion efficiencies devoid of thermal influences is pivotal for deepening our comprehension of PEC biosensing mechanisms.

MIL-125(Ti)–NH₂ was pyrolyzed in N₂ and H₂/Ar gas to prepare N-doped carbon materials containing TiO₂ (TiO₂-NC). XPS, ESR and Raman spectra analysis showed that higher concentration of oxygen vacancies were created on the surface of TiO₂ in H₂/Ar gas, which provided more anchor sites for the nucleation of Pt and enhanced the interaction between Pt and TiO₂. Therefore, the mass activity/specific activity of Pt/(TiO₂-NC)_HA catalysts for methanol oxidation was 510.7 mA mg⁻¹_Pt/2.84 mA cm⁻²_Pt, which was 3.1/1.4 times that of Pt/(TiO₂-NC)_N catalysts. Due to the enriched OH_ads on the suface of TiO₂ and the strong metal-support interaction between TiO₂ and Pt, Pt/(TiO₂-NC)_HA catalysts exhibited stronger resistance to CO_ads poisoning than commercial JM-Pt/C catalysts, thus showing more excellent catalytic activity and stability.

CO₂ evolution is involved in various main and side reactions of electrochemical systems, such as carbon corrosion reactions and alcohol oxidation reactions. Differential electrochemical mass spectroscopy (DEMS) has been intensively applied to analyze the partial current of the CO₂ evolution reaction in acidic and neutral electrolyte solutions. However, the quantitative analysis of the CO₂ evolution reaction in alkaline electrolyte solutions has not been successful when catalyst-loaded carbon electrodes were applied, due to the high solubility of CO₂ in the electrolyte. In this study, we develop a new DEMS system combining microreactor and ion exchange membrane to quantitatively analyze CO₂ evolution reactions of catalyst-loaded carbon electrodes in alkaline electrolyte solutions. The calibration constant, which correlates the mass signal of m/z = 44 to the partial current of the CO₂ evolution reaction, is successfully obtained from the Faradaic current and the mass signal of CO stripping voltammetry. We analyze carbon corrosion reactions of Pt and metal oxide-loaded carbon electrodes to demonstrate the effectiveness of the constructed system. The corrosion behavior of the Pt-loaded carbon is similar to that in the acidic electrolytes except for the onset potential of the carbon corrosion. La_0.6Ca_0.4CoO₃ and Ca₂FeCoO₅ show electrochemical carbon corrosion activity, while La_0.4Sr_0.6MnO₃ does not show distinct electrochemical carbon corrosion activity.

In the present research, ZnO@TiO₂ nanoparticles (ZnO@TiO₂ NPs) was synthesized by using a simple method and the results of infrared (IR), X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and energy-dispersive X-ray spectroscopy (EDX) confirmed their synthesis. Then, an electrochemical sensor based on screen printed graphite electrode (SPGE) modified with ZnO@TiO₂ NPs was developed for voltammetric detection of hydrazine in water samples. The ZnO@TiO₂ NPs modified SPGE demonstrates significant performance toward the hydrazine detection due to the synergistic effect between ZnO NPs and TiO₂ NPs and it proved by the results from cyclic voltammetry (CV). Also, the observation of an oxidation peak without a reduction peak in the opposite scan direction indicated the irreversibility of the electrochemical oxidation of hydrazine on both the bare SPGE and the ZnO@TiO₂/SPGE. Under optimized conditions (pH and differential pulse parameters), the voltammetric current response of hydrazine at the ZnO@TiO₂/SPGE showed linear dependence on the concentration, ranging from 0.01 µM to 585.0 µM with a limit of detection (LOD) of 0.005 µM. In addition, the pertinency of the ZnO@TiO₂/SPGE sensor for practical applications was investigated by quantification detection of hydrazine in water samples. The findings showed recovery values between 97.3 % and 104.2 % and relative standard deviations (RSDs) ≤ 3.5 % for river and tap water samples.