Electrochemistry Communications最新文献

Solid-state batteries that utilize sulfide-based solid-electrolytes, such as the argyrodite Li₆PS₅Cl, have become one of the most promising directions for next-generation energy storage. However, one remaining technical challenge for such materials has been the requirement of large pressures during operation. This challenge grows as the size of the cells increase as the pressure must be uniformly distributed over a larger-and-larger area. In this work, we introduce an isotropic cell design to pressurize the cell with perfect homogeneity, which is ensured by using a fluid pressurization medium. By achieving perfect homogeneity, the magnitude of the pressure necessary to stabilize the material is greatly reduced. Using such an isotropic cell design, lithium-metal solid-state pouch cells achieve remarkable extreme-fast-charging performance even at a low-pressure of only 2 MPa.

The technology of 3D printing has emerged as a potent tool for the preparation of 3D-printed electrode. Using commercial graphene/polylactic acid (PLA) composite filaments as printed materials, fused deposition modeling as 3D-printed technique, 3D printed electrodes (3DEs) were created in this work. Gold nanoparticles (AuNPs) and the composites of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were used to modify the activated 3DEs for constructing a novel electrode (SACP@Au@3DE), and in this work chlorogenic acid (CGA) was regarded as a probe for testing the performance of SACP@Au@3DE. The surface physicochemical properties of the prepared 3DEs were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of the prepared 3DEs were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. The constructed SACP@Au@3DE can be used to determine CGA at concentrations ranging from 10 to 400 μM with a limit of detection (LOD) of 4.13 μM. Ultimately, the SACP@Au@3DE sensor was used for CGA detection in coffee powder sample to explore the potential for real sample analysis. This work opens the novel avenue of using conductive polymer modified 3D-printed electrode in the field of sensor.

Calcium ion is a type of indispensable metal elements in biology, which participates in processes like maintaining the excitability of neuromuscular muscles. However, calcium content should be monitored in a safety range. Herein, a novel electrochemical method is developed for Ca²⁺ assay by monitoring electrochemical response after DNAzyme catalyzed DNA hydrogel degradation. Pure DNA hydrogel is first built with three-way junction scaffolds and linkers containing Ca²⁺-dependent DNAzyme sequence. In the presence of target Ca²⁺, the substrates in linkers are cleaved and DNA hydrogel can be degraded gradually. The encapsulated electrochemical species thus facilely interact with the electrode, leading to the increase of electrochemical responses. This electrochemical method for Ca²⁺ quantification is selective and sensitive, which also performs satisfactorily challenging biological samples like sweat and urine.

Thermo-electrochemical cells (TECs) are able to convert heat into electricity. They are formed by two electrodes (typically Pt) separated by a redox electrolyte (usually 0.4 M aqueous ferro/ferricyanide). The widely adopted architecture of TECs consists of the two electrodes separated by an electrolyte channel. To our knowledge, no studies have been reported exploring a different architecture. Here, we evaluate an alternative configuration, which comprises a substrate with the two electrodes at its ends and with the electrolyte added on the top contacting both electrodes, forming a planar configuration. We explore first the use of the standard Pt electrodes deposited on top of a conductive glass substrate. Then, we replace the Pt by nanostructured and porous Sb-doped SnO₂. The planar configurations are compared with their corresponding typical architectures using the common ferro/ferricyanide electrolyte. It was found that the planar TEC with Sb:SnO₂ reached a temperature coefficient of 1.76 mV/K, higher than the value obtained in the standard configuration with Sb:SnO₂ (1.21 mV/K), and also higher than the planar architecture with Pt electrodes, which showed the typical value for the ferro/ferricyanide electrolyte (1.45 mV/K). As a consequence of this significantly larger value, a 29.7 % higher maximum power output than the planar TEC with Pt was observed. Our study identifies for the first time interesting new features when a planar architecture is employed, opening the door to explore in more detail this alternative configuration in TECs.

The quest for advanced energy storage solutions has intensified the focus on developing next-generation secondary batteries, with lithium-oxygen batteries (LOB) standing out for their superior theoretical gravimetric energy density. This study introduces a novel model-based approach to battery development, enabling the detailed analysis of charge–discharge cycles and oxygen evolution efficiency within a virtual environment. Our model distinctively simulates the oxidative decomposition of lithium peroxide (Li₂O₂) and differentiates between its formation through solution and surface pathways, addressing the complexities of the charging process and its multiple elementary steps. The developed model further categorizes the oxidative decomposition species into four distinct types, facilitating a comprehensive understanding of their interactions, voltage profile changes, and O₂ evolution within the battery's porous cathode. This approach not only enhances the understanding of battery behavior but also aids in refining the design of component materials, thereby propelling forward the development of LOBs with improved energy density and cycle performance.

Flavin is one of the most prevalent redox molecules utilized by electroactive bacteria. Electroactive bacteria form a three-dimensional architecture with multiple cell assemblages on electrodes in bioelectrochemical systems. This provokes the importance of unveiling the redox chemistry of flavins during electron transfer not only at the bacteria/electrode interface but also inside cell assemblages. However, it has been difficult to directly compare the redox species contributing to each electron transfer reaction. In this study, to simultaneously detect the flavin redox species at the electrode surface and those in cell assemblages, we conducted bipotentiometric cyclic voltammetry on a colony of Shewanella oneidensis MR-1. The bipotentiometric data showed that flavin mononucleotide proceeds the redox cycle at − 0.43 V (vs. standard hydrogen electrode) in the MR-1 colony assignable to the semiquinone/hydroquinone redox cycle, which was supported by experiments with semiquinone scavenger and gene deletion mutants. Notably, the peak at − 0.43 V was not detected at the electrode surface, indicating that the flavin redox cycles and redox potentials involved in the electron transfer inside MR-1 assemblages differ from those at the MR-1/electrode interface. The measurement system presented herein offers a platform to clarify the redox reactions in cell assemblages as well as at the bacteria/electrode interface.

Because of the growing high importance of the development of biocatalytic fuel cell (FC) technologies for renewable energy-producing and testing systems for medical or environmental purposes, in this study, we constructed and demonstrated an H₂ FC voltammeter working with graphite sample testing micro-strips and based on Escherichia coli microbial cells. Presented H₂ FC voltammeter that provides fast and precise testing of bio-electrochemical possible reactions in biosamples for H₂ and other gases, is automated with software which works in NI LabVIEW programming environment, has amplifier cascade system with high internal resistance, temperature controlling and resistance cascade. Microbial Hydrogenase (Hyd) enzymes reversibly catalyze the formation and oxidation of H₂. Isolation and characterization of O₂-tolerant [NiFe]-hydrogenases (Hyds) have given rise to new concepts in H₂ FC. Escherichia coli and [NiFe]-Hyds can be applied as a biocatalyst anode in biofuel cells (BFCs). We evaluated the efficiency of applying the 3 µl (1.5 mg cell dry weight) E. coli intact cells or crude extracts on 0.5 cm² as anode catalyzers in the bio-electrochemical system. The highest electrical potential (up to 0.7 V) was achieved with bacterial whole cells, which were grown on glucose and glycerol.

The effect of varying Al concentrations on the electrochemical corrosion resistance of binary Mg-Al solid solutions thin films under alkaline immersion conditions was investigated via a combination of in-situ flow-cell, scanning vibrating electrode technique and microscopy analysis. These spatially resolving characterization techniques are employed along the Al concentration gradient of the combinatorically grown thin films enabling efficient screening of the Al concentration dependent electrochemical corrosion behaviour. The analysis revealed an increasing corrosion resistance with increasing Al concentration, as a consequence of Al induced hydroxide reinforcement. Specifically, the addition of >4 wt.% Al decreases the corrosion current density in the range of 70–90 % compared to pure Mg.

Reliable electrochemical measurements depend on the availability of robust reference electrodes (RE) with well-defined potentials. While many reliable REs are known, they are not applicable in certain demanding media such as ionic liquids, nor in small confined spaces. Here, we describe the fabrication of a simple yet robust Ag/Ag₂S micro-reference electrode (μ-RE) where a micron-thick Ag₂S layer is formed by isothermal reaction with sulfur vapor. Scanning electron microscopy, X-ray photoemission spectroscopy, and spectroscopic ellipsometry characterization reveals that the optimal morphology corresponds to a slightly porous Ag₂S film. We demonstrate that the Ag/Ag₂S μ-RE can be operated in and cycled through a wide variety of polar organic solvents, including common protic solvents (EtOH), aprotic solvents (ACN, DMSO, NMP, DMF) and ionic liquids (EMIM-TFSI, BMP-TFSI), with short equilibration time (tens of seconds) and little drift (<20 mV), without requiring encapsulation, protective liquid junctions, nor special conditioning. A redox potential of 0.54 ± 0.02 V was obtained for ferrocene in acetonitrile, which places this RE at 0.08 V vs Ag/AgCl. We have also successfully embedded the electrode inside the CR2032 coin cell to perform cyclic voltammetry of battery materials. These results underpin the suitability of this simple micro-reference electrode for a wide variety of electrochemical measurements in demanding and/or miniaturized environments.

Aluminium-air batteries have been considered as one of the most promising next-generation energy storage devices. In this work, based on COMSOL Multiphysics, we firstly explored the effect of 3D pore size structure change on the permeation performance of the solution. The results showed that enhancing the permeation stroke of permeable solutions was beneficial to expanding the electrode reaction contact area, but it would reduce the permeation and corrosion resistance effects. For this reason, we further carried out a secondary study of TPMS structure on fluid permeation and its electrochemical performance based on the TPMS structure modelling mechanism. The results showed that the TPMS structure possessed both good solution permeation reaction rate and good corrosion resistance. Additionally, in order to further verify the validity of the simulation data, we carried out the validation of the self-corrosion rate, discharge properties, and electrochemical properties. From the final data, the discharge voltage of the TPMS structure was only 1.43 V, but its corrosion current and polarisation impedance were 2.207 × 10⁻² A/cm² and 2.2 Ω∙cm², respectively. At the same time, the structure also had good solution permeability. Therefore the porous anode structure design for aluminium-air batteries in three-dimensional state is preferred.