Anodic TiO2 nanotubes (ATNTs) have received much attention, but the classic field-assisted dissolution (FAD) mechanism involving the participation of fluoride ions has been questioned. Up to now, the relationship between the concentration of fluoride ions in the electrolyte and the growth rate of nanotubes has not been explained. In the same electrolyte with the same fluoride ion concentration, the growth rates of nanotubes obtained at 55 V, 60 V and 65 V are 156 nm/min, 215 nm/min and 402 nm/min. This paper considers why the FAD model involving fluoride ions cannot explain the huge differences in the growth rates. The huge difference is first interpreted reasonably in terms of the electronic current and the oxygen bubble model. The results show that the dissolution of oxide by fluoride ions is weak, and the role of fluoride ions is rather to form an anion-contaminated layer, which promotes the generation of electronic current and oxygen evolution. This theory was then tested by adding boric acid to the electrolyte. Borate can inhibit the penetration of fluoride ions into the contaminated layer, resulting in a significant reduction in electronic current, thus greatly reducing the growth rate of the nanotubes.

In this study, we introduce a novel method for synthesizing a free-standing, high-aspect-ratio TiO2 nanotubular (TNT) hybrid membrane. The TNT membrane was fabricated using a two-step electrochemical anodization process, incorporating lactic acid as an additive to enhance mechanical properties and growth rate. The membrane was then hybridized with a rubber polymer binder. The high aspect ratio and structural integrity of the TiO2 nanotubular hybrid membrane make it an ideal candidate for improving non-flammable properties when employed as a ceramic separator. Flame retardation tests revealed that the TNT hybrid membrane kept its structural integrity even after prolonged exposure to flame. These findings suggest that this hybrid membrane could be a valuable addition to the field of secondary batteries, offering potential applications in enhancing battery safety and performance.

In recent years, electrochemical exfoliation of layered materials has attracted increasing attention owing to its wide feasibility in the fast and high-yield preparation of various two-dimensional (2D) nanomaterials. This process typically involves the use of an electric field to drive the intercalation of counter ions into the layered structure. The regulation of the interlayer chemistry plays a crucial rule in electrochemical exfoliation, yet it is often overlooked in existing review articles. To fill this gap, we present a summary of the most recent progress made in understanding the role of interlayer chemistry regulation in electrochemical, with a particular emphasis on the impact of redox reactions that lead to the electrochemical degradation of electrolytes and solvents, as well as the covalent modification necessary for creating 2D functional derivatives. The opportunities and challenges in this field are provided in the end, with a focus on the critical roles played by the electrochemical kinetics and interface observation in the development of large-scale industrial methods. These factors are pivotal for the continued progress and advancement of prospective techniques in this area.

In recent years, the critical need for better performance, higher safety, and longer cycle life in lithium-ion batteries has become so tangible and ubiquitous that an increasing amount of effort has been focused on the search for new materials. However, in contrast to the search for advanced and efficient materials, electrode engineering is a practical way to enhance battery performance. Here, we show that the electrochemical performance of the NMC811 electrode containing functionalized powder (Carbon Black KS6) can be remarkably enhanced by fabricating cathodes with an out-of-plane aligned architecture. The aligned architecture results in faster charge transport kinetics and a specific charge up to two times higher than that of non-architectured electrodes at a rate of 5C.

Template-assisted electrodeposition is a versatile technique for preparing metal nanostructures, e.g. nanowires and nanotubes, in anodic aluminium oxide (AAO) templates with cylindrical channels. However, the fraction of pores in which the electrochemical process occurs is not known in advance, which makes coulometric control of the deposition process nontrivial. In this paper, we propose a simple method for determining the fraction of active nanopores, i.e., pores in which metal is deposited. This is based on the analysis of current transients registered during templated electrodeposition. The developed method makes it possible to estimate the density of deposited nanowires and their average length by coulometric control without using scanning electron microscopy.

The oxidation of water is quite popular and essential in practical applications for human beings. MnOx as electrocatalysts has the merits of robust durability and activity even in acidic mediums. Reaction mechanisms for OER on MnOx in acid are summarized at an atomic level. The influences of the crystal facets of MnOx on OER in acidic mediums are discussed theoretically and experimentally. Moreover, practical applications of pure MnOx in PEM-based water electrolysis are put forward and highlighted. Various Mn-based heterogeneous catalysts with earth-abundant or noble metals incorporation are reviewed. This study offers several strategies to enhance the activity and durability of the MnOx based electrocatalysts.

The anode-less lithium battery with the structure of lithium nickel manganese cobalt oxide (LiNi0.33Mn0.33Co0.33O2, NMC111) /gel polymer electrolyte (GPE)/silver (Ag)/ conductive carbon black (CCB) coated aluminum current collectors has been proposed for high energy density in this research. The results indicate that the anode-less lithium battery on Ag/CCB-coated aluminum current collector has a sufficient discharge capacity of 0.935 mAh/cm2 and exhibited capacity retention of 86.1 % after 30 cycles of the charge–discharge test. This 1st lower coulombic efficiency (discharge capacity/charge capacity × 100 %) only goes to 46.8 % due to the Li-Al alloying reaction, and part of the lithium ions reacted with the GPE, CCB, and aluminum current collector during the 1st cycle of the anode-less NMC111 lithium battery. These accompanying reactions consumed the Li ions and resulted in the irreversible capacity in the 1st cycle. However, the coulombic efficiency has increased to about 96.2 % after the 1st cycle test. This result indicates that most of the charge–discharge cycles reacted in a reversible capacity, and the anode-less NMC111 lithium battery has the potential for high energy density application.

A wide electrochemical window makes boron-doped diamond (BDD) a promising electrode material. To utilize its excellent properties, nanopore formation on the surface to increase the specific surface area is highly desirable. Although anodization has the potential to produce nanoporous structures on the surface of materials, BDD has yet to be anodized due to its high physical and chemical stability. Here, we report that high-energy Si(II) ion irradiation forms sp2 defects, which enable the anodization of BDD, and demonstrate that this anodization results in the formation of nanoporous BDD.

This study presents the results of an alkaline-acidic ethanol electroreformer producing hydrogen and electricity simultaneously. This is due to the pH gradient between an alkaline anolyte/fuel (1 mol/L ethanol and 4 mol/L KOH) and an acidic catholyte/comburent (1 mol/L H2SO4), separated by a K+-pretreated Nafion® 211 membrane to prevent chemical neutralization, resulting in an extra electromotive force. At 70 °C, the electroreformer delivers a maximum power density of 23 mW cm−2. An increase in the flow rate from 0.17 to 1.12 mL min−1 is also beneficial due to the mass transport enhancement. Finally, over the stability tests for 3 h at 50 °C and a flow rate of 1.12 mL min−1, it is possible to produce H2 at an average rate of 0.218 and 0.267 STP m3 m-2h−1, and an average energy of 0.0877 and 0.0997 kWh m−2 in recirculation and single-pass mode, respectively. The worse performance in the recirculation mode seems to be due to the accumulation of the ethanol electro-oxidation products, resulting in the poisoning of the catalyst surface.

Previous electrochemical studies of redox emulsions have been mainly performed in the context of electro-organic synthesis. More recently, this research has been oriented towards applications of emulsions in flow batteries. Such biphasic systems seem to provide a suitable environment for reactions at the liquid–liquid interface. Taking an emulsion consisting of microdroplets of decamethylferrocene solution in a hydrophobic ionic liquid/toluene mixture in acidic aqueous solution as an example, we have demonstrated that an electrochemical redox reaction involving the hydrophobic redox probe occurs at the glassy carbon electrode|organic liquid film interface. This reaction is followed by ion exchange between liquid phases. This effect is explained by the instability of the emulsion. A portion of the organic liquid stays on the electrode surface after transfer to a purely aqueous electrolyte and remains electroactive.

Substances inhibiting specific proteins involved in cellular electron transfer chains are used in biochemical research to investigate intracellular electron transfer routes and to redirect the electron fluxes. This also provides an in vivo approach to investigating the extracellular electron transfer (EET) mechanisms within and across biological membranes in bioelectrochemical research. However, the applicability of these specific inhibitors in electrochemical systems remains to be validated, particularly when aiming for (semi-)quantitative evaluation of the contribution of specific redox proteins to the EET. Here we conducted a systematic analysis of commonly used inhibitors and discovered several of them to be electrochemically active and thus capable of interfering with measurements in a bioelectrochemical reactor system in abiotic experiments. We also observed effects in vivo using a biophotovoltaics reactor with Synechocystis sp. PCC 6803 as a model system.

Model measurements of an equivalent electrical system were carried out using the technique of Dynamic Electrochemical Impedance Spectroscopy. The measurement took the form of potentiodynamic changes imposed on the tested system. Using the possibility of continuous impedance measurements, an attempt was made to develop an original and innovative method of analyzing impedance spectrograms, which is termed polynomial analysis. As a result of this approach, it is possible to generate two novel impedance spectra from the primary impedance spectrogram. The innovation lies in the use of simple polynomials to describe a set of spectra, and then performing differential and division operations, which result in differential- and relative-impedance spectra. Among other things, differential spectra have the ability to track the rate of change in impedance as a function of an independent variable. By contrast, relative impedance spectra eliminate surface influence, which opens the way to the direct comparison of physicochemical processes and more.

The in situ voltammetry of blueberry fruits and microparticulate deposits from their ethanolic extracts reveals the appearance of a prominent oxidation signal at ca. − 0.7 V vs. Ag/AgCl. This only appears in the presence of O2 under conditions in which the superoxide radical anion is generated initially. This feature, mainly associated with anthocyanins, is in agreement with SECM examination of blueberry thin epithelial films, and suggests that there is reactive oxygen species (ROS)-assisted promotion of the antioxidant capacity of anthocyanins accompanying the phenoxide-mediated ROS reactivity of these compounds.

Nickel-rich cobalt-free layered cathode materials are expected to meet the urgent demand for high-energy batteries at an adorable cost. However, as the nickel content increases and cobalt content decreases, layered cathode materials suffer from serious structure degradation and capacity fade during cycling. The large amount of residual lithium in nickel-rich materials also brings difficulties to industrial manufacturing and challenges battery safety. In this work, well-formed crystal cobalt-contained coatings with surface cobalt-doped ultrahigh-nickel-based layered LiNi0.95Mn0.05O2 cathode material is synthesized through solid solution and post-heat treatment with Co(OH)2, during which the residual lithium is significantly consumed. The optimized sample acquired at 650 ℃ shows an increased discharge capacity of 221.2 mAh g−1 from 219 mAh g−1 of the pristine one at 0.1 C and the capacity retention is enhanced from 72.6% to 83.2% for 100 cycles at 0.5 C.

In this paper we present the characterization of 3D-printed nanocarbon electrodes (3DnCes) and their application in electrochemical enzyme-linked detection of DNA hybridization. The approach takes advantage of a facile procedure based on adsorption of target DNA on the electrode surface followed by hybridization with a biotinylated probe and binding of streptavidin–alkaline phosphatase conjugate. The alkaline phosphatase converts 1-naphthyl phosphate in the background electrolyte into electrochemically oxidizable 1-naphthol, which is subsequently detected using linear sweep voltammetry. The preparation, characterization, and analytical performance of the 3DnCes are reported. The results show the applicability of such 3DnCes in detection of target DNA hybridization specifically with the complementary biotinylated probe, and indicate the potential of 3D printed electrodes for use in various bioanalytical approaches.

For solid-state electrolyte in lithium-ion batteries, high crystal boundary impedance leads to tough electrolyte-electrode interfacial issues. Here, we introduce garnet Li6.4La3Zr1.4Ta0.6O12 (LLZTO) nanoparticles and succinonitrile (SN) into thermal polyurethane (TPU) to fabricate a composite solid-state electrolyte (TPU/LLZTO/SN), achieving high ionic conductivity of 6.452 × 10−4 S cm−1. The TPU polymer with specific soft and hard segments allows lithium ions fast transport and holds good mechanical strength as the electrolyte matrix. The ionic conductor LLZTO further improves the ionic conductivity and mechanical property of the composite electrolyte membrane. Additional SN supplies the electrolyte’ wide electrochemical stabilization window, and enhances the metallic lithium compatibility of the TPU matrix. As a result, the as prepared TPU/LLZTO/SN electrolyte presents high lithium ions transference number of 0.64, and also good mechanical property.

Solid-state lithium-metal batteries with lithium-metallic as anodes have attracted countless attention by virtue of their high energy density and safety, in which solid electrolytes with the high mechanical strength, ionic conductivity, and compatible interface are the significant key in suppressing the growth of dendrites and eliminating the risk of inner short circuits. The introduction of fillers into poly(ethyleneoxide)(PEO)-based solid polymer electrolytes is well regarded as an effective routine to modify their mechanical and electrochemical properties. Metal–organic frameworks (MOFs), a type of porous crystalline materials composed of inorganic metal ions and organic ligands, have drawn broad research interest, presenting giant potential in the fabrication of high-performance SSEs due to their abundant porosity and controllable functionality. In this review, the applications of metal–organic frameworks in PEO along with their electrochemical performance in solid-state lithium-metal batteries are outlined.

Next-generation Li-ion batteries (LIBs) require fast charge–discharge operations, during which a steep concentration gradient (CG) is formed between the two electrodes. The formation of a concentration profile between the electrodes in a LIB with a solvate ionic liquid is observed at a distance of less than 1 mm using holographic interferometry. This in situ technique enables the visualization of concentration profile formation near both electrodes during electrolysis, which relaxes after the electrolysis is stopped. The diffusion coefficients near both the electrodes are calculated from the concentrations of transient species near the electrode surfaces. The diffusion coefficient is smaller on the anode side of the cell than on the cathode side owing to the viscosity of the electrolyte in the diffusion layer. This viscosity effect may have caused the concentration profile to become asymmetrical during the relaxation of the CG.

The measurement of single soft bio-particles has been regarded as one of the “holy grails” in the field of analytical chemistry. As a frontier of electrochemical analytical tool, single-particle impact electrochemistry (SPIE) allows in situ detection and counting of a variety of soft bio-particles, e.g., liposomes, viruses, bacteria and cells in a simple and fast way. In this review article, we summarize the representative work of SPIE based soft bio-particle analysis, categorized by the detection principle, namely diffusion blocking, redox labeling or/and mediating and direct electrolysis. A discussion of further considerations worth investigating in the future is followed.

Electrochemical impedance spectroscopy (EIS) is a powerful tool in characterisation of processes in electrochemical systems, allowing us to elucidate the resistance and characteristic frequency of physical properties such as reaction and transport rates. The essence of EIS is the relationship between current and potential at a given frequency. However, it is often the case that we do not understand the electrochemical system well enough to fit a meaningful physical model to EIS data. The distribution of relaxation times (DRT) calculation assumes an infinite series of relaxation processes distributed over a characteristic timescale. The DRT calculation may identify the number of processes occurring, as well as their respective resistivity and characteristic timescale, and may resolve processes which have relatively similar timescales. Using a nonparametric tool known as Gaussian process (GP) regression, we showcase a method of finding a unique solution to the ill-posed DRT problem by optimising kernel hyperparameters as opposed to ad-hoc regularisation. In this work, we use finite GP regression under inequality constraints (fGP) to analysed EIS data generated by a (Ni/CGO|CGO|YSZ|Reference Cathode) solid-oxide fuel cell in a gas mixture of 0.5 bar H2/0.5 bar H2O and at a temperature of 600 °C. By varying the current density, we can characterise the current-voltage relationship of the electrode and shed light on the reaction mechanism governing charge transfer at the solid-gas interface. Our findings also show that even at relatively high current densities (±600mAcm-2) the electrode process is limited by charge transfer.