ChemElectroChem最新文献

In pursuit of efficient and cost-effective grid-scale energy storage solutions, redox flow batteries (RFBs) have emerged as champions by offering a promising solution owing to their design scalability. However, conventional vanadium RFBs are limited by high and volatile material costs. Here, a novel vanadium–titanium RFB (VTRFB) is presented that combines the redox potential of vanadium (V⁵⁺/V⁴⁺) with the low cost and natural abundance of titanium (Ti³⁺/Ti⁴⁺). The VTRFB delivers a long-term performance over more than 500 h (>150 cycles), maintaining ≈100% coulombic efficiency (CE%) and ≈80% voltage (VE%) and energy (EE%) efficiencies. Furthermore, the RFB also reaches an energy density of ≈21.8 Wh L⁻¹ with a stable nominal discharge voltage of 0.9 V. To advance sustainability and green chemistry, the vanadium catholyte is replaced with a BmimCl-based ionic-liquid formulation, and a cost-effective SPEEK membrane is incorporated. Both modifications preserve CE > 90% and VE%/EE% above 50%, demonstrating that the system remains robust even under greener and lower-cost configurations. This VTRFB design integrates low-cost materials and high electrochemical performance, representing a significant step toward next-generation sustainable RFBs.

An electrochemical approach for the regeneration of tetramethyl orthosilicate (TMOS) from hexamethoxydisiloxane (HMDS), which contains electrochemically inert SiO bonds, is presented. This transformation relies on the in situ generation of methoxide ions under cathodic conditions as the key reactive species and the efficient capture of the water produced during the reaction using molecular sieves 3A (MS3A). In addition to the key role of methoxide, mechanistic studies revealed that its gradual electrochemical generation, which is balanced by the anodic generation of protons, maintains a neutral to mildly basic reaction environment. This acid–base balance is crucial to suppress undesired hydrolysis and oligomerization of siloxane species. The reaction proceeds at ambient temperature, which allows using MS3A in a single vessel, thus enabling an operationally simple and energy-efficient process without the need for heating or metal catalysts.

Hydrogen is a promising clean energy carrier amid growing energy demand and fossil fuel depletion. Conventional water electrolysis suffers from the sluggish oxygen evolution reaction (OER) at the anode. Carbon-assisted water electrolysis (CAWE) offers a promising alternative by replacing the OER with the carbon oxidation reaction (COR), which significantly lowers the theoretical thermodynamic barrier and enables highly efficient hydrogen production. Nevertheless, carbon materials tend to degrade during oxidation, leading to reduced electrode stability and performance. In this study, Fe-N-C structured biochar catalysts are developed to regulate the electronic structure and physicochemical properties of the material, thereby enhancing its corrosion resistance and COR activity. The optimized catalyst exhibits excellent COR performance in 1 mol L⁻¹ KOH solution, delivering a current density of 42.7 mA cm⁻² and an energy consumption of only 0.0079 Wh at a current density of 10 mA cm⁻², ≈28% lower than that of conventional Pt-based anodes. Further characterization through X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, transmission electron microscopy, and density functional theory analyses reveals the synergistic effect of Fe-N-C sites, providing both theoretical and experimental insights into the design of high-efficiency catalysts for electrolytic hydrogen production.

At positive electrode potentials, adsorbed SO₄ (blue central atom) and H₂O form an ordered adlayer at the Au(111)-electrolyte interface (shown in the background). During this transition, chains of closely spaced SO₄ adsorbates emerge. These chains are stabilized by coadsorbed H₂O, enabling electron redistribution between the hydrogen-bonded adsorbates, as supported by DFT and AIMD analyses. This uncovers a unique adsorbate-adsorbate interaction where electrons delocalize between adsorbate pairs. More information can be found in the Research Article by Jan Rossmeisl and co-workers (DOI: 10.1002/celc.202500311).

Aqueous processing of cathodes offers a lower-cost, greener alternative to poly(vinylidene fluoride)/N-methyl-2-pyrrolidone routes, but contact with water elevates slurry pH and drives metal leaching, causing Al current-collector corrosion and electrode voids. Strong acids (e.g., H₃PO₄) can curb corrosion yet often disrupt rheology, increase leaching, and weaken adhesion. Herein, lithium dihydrogen phosphate (LiH₂PO₄) is introduced as a lithium-containing pH buffer (H₂PO₄⁻/HPO₄²⁻ near-neutral pH) for water-based processing of LiNi_0.6Co_0.2Mn_0.2O₂ (NMC622) and Li[Ni_0.5Mn_1.45Al_0.05]O₄ (LNMO). Slurry pH evolution and transition-metal dissolution under H₃PO₄ versus LiH₂PO₄ dosing are quantified and showing that LiH₂PO₄ more effectively stabilizes pH and suppresses leaching. Electrodes cast with LiH₂PO₄ additives display reduced Al pitting, crack-free coatings with good adhesion, and improved cycling stability. X-ray photoelectron spectroscopy detects surface phosphorus species consistent with a thin phosphate passivation layer. These results establish LiH₂PO₄ as a simple, scalable additive that enables robust aqueous processing of high-voltage cathodes without the side effects associated with strong acids.

Water electrolysis is a promising route to green hydrogen production, but its operation in chloride-containing electrolytes (e.g., seawater) is hindered by the competing chlorine evolution reaction (CER) that lowers oxygen evolution reaction (OER) selectivity and accelerates catalyst degradation. Here, we use a combination of electrochemical quartz crystal microbalance (EQCM) and operando Surface-Enhanced Raman spectroscopy (SERS) to directly probe chloride adsorption on Ni-based catalysts. Our study reveals that chloride ions (Cl⁻) adsorb on the Ni surface even at low potentials where Ni(OH)₂ is the predominant phase, and that this adsorption intensifies on high-valent Ni OOH during OER, leading to hypochlorite (OCl⁻) formation significantly reduce OER selectivity and catalyst stability. Importantly, introducing spectator anions such as CO₃²⁻, SO₄²⁻, or NO₃⁻ suppresses Cl⁻ adsorption. Among these, CO₃²⁻ binds strongly to Ni sites and inhibits both Cl⁻ and OH⁻ adsorption, whereas SO₄²⁻ and NO₃⁻, with their weaker binding, preferentially block Cl⁻ while still allowing OH⁻ adsorption. As a result, OCl⁻ generation is dramatically decreased even under locally acidic conditions caused by high OER current densities, thereby enhancing catalyst activity and stability by selectively favoring OER over CER. This study highlights the utility of combined EQCM–SERS analysis to unravel interfacial adsorption processes in complex electrolytes like seawater splitting and provides new insights into leveraging adsorption preferences of spectator anions.

Additive manufacturing has emerged as a versatile platform for electrode fabrication, offering cost efficiency, design flexibility, and compatibility with a wide range of materials. Electrochemical dehalogenation represents a critical strategy for the removal of toxic halogenated organic pollutants, such as chloroacetic acids, which pose significant environmental and health risks. The use of earth-abundant metals, including iron, copper, and nickel, as well as carbon-based materials, further enhances the sustainability and scalability of this approach. This concept article describes the electrochemical reduction of trichloroacetic acid at conventional electrodes and reviews the current state of research on electrochemical dehalogenation at additively manufactured electrodes. From this perspective, the further integration of advanced fabrication techniques, along with the application of machine learning and artificial intelligence, presents significant opportunities for innovation in materials and processes. In addition to electrode fabrication, the incorporation of in situ spectroscopy is proposed to gain deeper insight into the underlying reaction mechanisms. To bridge the gap between fundamental research and the implementation of new processes in industrial applications, a series of process optimization strategies is also outlined.

During aluminum (Al) electrolysis, large amounts of spent cathode carbon (SCC) are generated, often contaminated with hazardous substances such as fluorides and cyanides. As a result, SCC is classified as a dangerous solid waste posing long-term risks to ecosystems and human health if untreated. This review comprehensively analyzes the chemical composition, formation mechanisms, and environmental hazards of SCC, and summarizes current physical and chemical remediation strategies. Unlike previous reviews, it integrates a comparative life cycle assessment (LCA) to evaluate the environmental performance of different SCC treatment routes, offering a holistic view of their sustainability. Additionally, it highlights opportunities for recovering valuable elements, particularly carbon (C), fluorine (F), and lithium (Li), and explores high-value recycling pathways such as battery anodes, graphene, and SiC semiconductors. Although many studies focus on laboratory-scale recovery efficiencies, environmental sustainability assessments remain scarce. Integrated processes including molten salt roasting, ultrasonic-assisted leaching, and cryolite regeneration show promise for detoxification and resource recovery. However, challenges such as C passivation, fluoride stabilization, and high energy demands persist. By combining technological and environmental perspectives, this review provides a framework for developing scalable, low-emission SCC recycling technologies aligned with circular economy principles.

Halide perovskites have attracted significant interest due to their potential in optoelectronic devices. However, challenges related to complex compositional spaces, environmental sensitivity, and stability limitations continue to constrain their systematic development and application. Machine learning (ML) has emerged as an effective tool to address these challenges by enabling the prediction of material properties, the identification of promising compositions, and optimization of processing conditions, while reducing reliance on conventional trial-and-error methods. By capturing complex, nonlinear relationships among compositional, structural, and processing parameters, ML enables the exploration of broad design spaces that are essential for advancing perovskite research. Additionally, ML accelerates the discovery and optimization of perovskite materials through data-driven approaches, including high-throughput screening and inverse design, enabling rapid identification of optimal compositions and processing conditions for enhanced device performance and stability. This review provides an overview of recent efforts to integrate ML into halide perovskite studies, discussing workflows, implementation strategies, and notable progress in device-level development. This article highlights how ML enables systematic materials discovery and optimization, supporting the advancement of stable and efficient perovskite optoelectronic devices.

In this work, the coadsorption of SO₄ and H₂O at the Au(111)-electrolyte interface is investigated. It is uncovered how electron redistribution between coadsorbates correlates with the formation of tightly packed (√3a) SO₄-adsorbate chains, which have been previously observed by Video-scanning tunneling microscopy (STM) at potentials preceding the disorder-order transition into (√3 × √7) SO₄ adlayers, as reported by Suto and Magnussen. Using density functional theory, ab initio molecular dynamics is combined with static ground-state calculations to capture both the dynamic aqueous environment and the stability of coadsorbed SO₄ and H₂O species. The analysis is extended to AuPdPt(111) solid solutions, where simple linear adsorbate scaling relations are employed to probe the electronic environments and hydrogen bond interactions between the coadsorbed species at the metal surfaces. Variations in these scaling trends are consistent with partial surface bond transfer between coadsorbed SO₄ and H₂O, increasing the stability of such adsorbate configurations. Multiple unique adsorbate structures are consided, of which the √3a chains, previously observed by Video-STM, emerge as the most favorable pretransition configuration because they maximize the number of SO₄–H₂O interactions and thus the extent of surface bond transfer as highlighted by the scaling trends.