ChemElectroChem最新文献

Anode-less solid-state batteries offer a pathway to maximize energy density while simplifying device manufacturing. However, the absence of an initial lithium (Li) reservoir demands precise control over Li deposition, a process usually hindered by interfacial instability and the lithiophobic nature of commonly employed current collectors (CCs). Therefore, effective interfacial design is crucial. In this regard, metallic and oxide interlayers offer a promising strategy to improve Li deposition, but detailed insights into their electrochemical behavior in combination with solid electrolytes (SEs) remain poorly understood. Accordingly, we engineer 50 nm thick zinc (Zn) and copper oxide (Cu₂O) interlayers sputtered directly onto the LLZO SE, covered by a 600 nm thick Cu CC. The interlayer composition and Li deposition behavior were investigated by using a range of techniques. The results demonstrate that Zn interlayers facilitate Li deposition via in situ formation of Li–Zn alloys. Differently, the Cu₂O interlayers drive Li₂O formation, which contributes to more homogeneous Li deposition. The stability of alloying and conversion processes are studied to assess the impact on cycling performance. Overall, this work provides insights into the implementation of alloying and conversion-based interlayers in solid-state anode-less systems and highlights key performance-limiting factors, offering interfacial design strategies for further improvement.

The current work focuses on the process parameters to enhance the current efficiency for the electrosynthesis of ammonium persulfate (APS) in a flow reactor under acidic environments using platinized titanium (Pt–Ti) as an anode. The effect of flow rate, current density, material of cathode, and separators on current efficiency for the preparation of persulfate is studied. Ammonium persulfate is produced by the reactor with a yield of 98.3% and a concentration of 100.32 g L^–1, indicating the effective performance of the proposed system. A maximum current efficiency of 74.9% is achieved, corresponding to the energy consumption of 2.9 kWh kg^–1 of ammonium persulfate using SS 304 and Daramic HD as cathode and separator, respectively. The impact of electrolyte composition on oxygen evolution reaction and hydrogen evolution reaction is investigated using linear sweep voltammetry. This selective cathode material and separator used in this flow system not only improve the yield and energy efficiency of ammonium persulfate production but also establish a scalable and sustainable method suitable for industrial applications.

Efficient alkaline water electrolysis requires highly active electrodes for the sluggish oxygen evolution reaction (OER). NiFeO_xH_y materials are among the most active OER electrocatalysts, and their activity can be tailored, among other methods, by electrochemical conditioning. However, there is a lack of systematic approaches to optimize the conditioning process to achieve the best electrode activation. A promising way to develop such approaches is to use mathematical models. While mechanistic models are not readily available and hard to develop, data-driven models might offer a straightforward alternative. The use of Bayesian optimization (BO) with Gaussian processes to improve the electrode conditioning process of a Ni-Fe bulk electrode is proposed. With this approach, an electrode conditioning process yielding a stronger activity enhancement compared to previous manual optimization is identified; at the same time, fewer experiments are also required. It is further shown that this also allows to transfer knowledge to new materials: transfer learning starting from the experimental data for the Ni-Fe electrode allows optimization of the conditioning of a Ni electrode with fewer experiments than applying BO to the Ni electrode from scratch. Overall, the potential of using data-driven numerical optimization in a hardware-in-the-loop approach for electrode conditioning is highlighted.

Aryl organoboron reagents play an important role in modern organic synthesis, and interest in radical-based coupling reactions from these precursors has grown rapidly. However, direct electrochemical generation of aryl radicals from aryl boronic acids, ArB(OH)₂, remains understudied due to their high oxidation potentials (E_ox > 2 V vs. Fc/Fc⁺) and challenges associated with electrochemical processes such as electrode passivation. Aryl potassium trifluoroborate salts (ArBF₃K) can be oxidized efficiently to aryl radicals is previously reported using alternating polarity electrolysis. Building on this, it is combined alternating polarity electrosynthesis with in situ fluoride activation to generate redox-active aryl fluoroborate intermediates, ArBF(OH)₂ and/or ArBF₂(OH), which have significantly lower oxidation potentials than their parent boronic acids or trifluoroborates. Moreover, it is found that for highly electron deficient aryl boronic acids with oxidation potentials higher than 1.7 V versus Fc/Fc⁺, a different mechanism is proposed where aryl boronic acids underwent ipso-substitution with oxidatively generated P(OEt)₃ radical cation. Overall, this dual mechanistic pathway allows an efficient radical-based functionalization of a broad range of aryl boronic acids to form aryl CP bonds.

Deep eutectic solvents (DES) are investigated since 20 years as ionic liquids alternative for electrochemical applications due to their reduced toxicity and cost. Metal electrowinning, is a process which is especially attractive for DES, since it allows the replacement the polluting state-of-the-art hydrometallurgical routes. Though, the solvent interest is conditioned to the DES long term stability under operating conditions. In this article experimental proofs of the long term stability of Propeline 1:3 both in storage and under electrochemical operation conditions, is provided using silver electroleaching- electrodeposition process as a model electrochemical system for the DES aging study. The solvent long term stability is evaluated during prolonged storage without electrochemical stress, providing a baseline for long-term usability. The electrochemical stability window of Propeline 1:3 is then determined, and its electrochemical degradation is forced for days in order 1) to identify degradation products and 2) to understand degradation mechanism that DES can encounter during extreme operating conditions. Finally, Propeline 1:3 long-term stability under operation conditions is evaluated using different electroleaching-electrodeposition current densities by the monitoring of degradation product formation. The impact of DES aging on the performances of silver electrowinning is assessed through a comparative analysis of fresh and aged electrolyte.

Arsenic contamination in drinking water remains a critical global health concern, with inorganic arsenic species like arsenite (As(III)) and arsenate (As(V)) posing severe toxicity risks, including carcinogenic and systemic health effects. Recognized as a Group 1 carcinogen by the International Agency for Research on Cancer, arsenic necessitates stringent monitoring to comply with the World Health Organization's (WHO) permissible limit of 10 ppb. Traditional analytical methods such as atomic absorption spectroscopy (AAS) and inductively coupled plasma-mass spectrometry (ICP-MS) provide high precision but are constrained by high costs, operational complexity, and lack of portability, thereby limiting their accessibility in resource-constrained and out-of-laboratory settings. Previous work by the authors explored the methods of arsenic detection and determination by covering most of the analytical methods and techniques, including various sensors and biosensor advancements. This review delves into the progress made predominantly over the last two decades in electroanalytical detection methodologies, which have gained momentum due to their rapid response time, high sensitivity, and adaptability for portable and cost-effective sensing platforms. Unlike most of the material-focused articles, this review presents recent advances in arsenic detection using various electroanalytical techniques—stripping voltammetry, pulse voltammetry, sweep voltammetry, combined voltammetry approaches, amperometry, and electrochemical impedance spectroscopy. The review covers necessary fundamentals of electroanalytical techniques, recent advancements, and emerging trends in arsenic sensor development. The review further explores the portable and onsite electrochemical arsenic sensors, followed by the main challenges and future outlook in this space. The integration of nanomaterials, screen-printed electrodes, and microfluidic devices has significantly improved the detection capabilities. However, standardization, reliability, scalability, speciation, and seamless data integration remain pressing challenges. Smartphone-integrated electrochemical sensors and AI-driven data analytics have the capabilities to foster real-time and onsite arsenic detection with enhanced performance. By leveraging sustainable materials innovations, miniaturized electrochemical platforms, and smart data handling approaches, next-generation arsenic sensors hold promise for ensuring safe drinking water in vulnerable and remote communities worldwide.

Layered oxides such as the Mn-rich lithium nickel manganese cobalt oxides are promising next-generation lithium-ion battery cathode materials owing to the abundance and environmental benignity of Mn. However, the first-cycle irreversibility loss and voltage decay remain key drawbacks that need to be addressed urgently. Herein, rational microwave irradiation is used to induce in situ generation of spinel phase in the bulk of a LiMn_0.662Ni_0.173Co_0.165O₂ material. The layered-spinel heterostructured cathode material delivers excellent cycling stability, with a continuous increase in discharge capacity until the 80th cycle at 0.1 C, thereafter showing a capacity decay of 12.9% when further cycled for 70 cycles, while also displaying suppressed voltage decay 4.11 mV cycle⁻¹ throughout these 150 cycles. Electrochemical impedance spectroscopy studies also show improved lithium diffusion kinetics. To establish the underlying science behind the impact of microwave irradiation, several characterization techniques attribute the observed excellent performance to i) lattice expansion, ii) suppressed Li⁺/Ni²⁺ cation mixing, iii) fine-tuned morphology, iv) increased average manganese oxidation state, and v) increased lattice oxygen in the material. This work showcases the potential of microwave-assisted synthesis methods in designing cathode materials with tuned physico-chemical properties, and thus improved electrochemistry.

This cover artwork depicts bioelectrocatalytic hydrogen evolution reaction by an artificial enzyme at an electrode surface. Artificial enzymatic electrochemistry is an emerging strategy to achieve desirable reactivity by coupling the expanded catalytic capabilities of artificial enzymes with the control of electrochemical approaches. This comprehensive review discusses promising artificial enzymes for reactions including HER, CO₂RR, and OER and highlights future directions in the field of artificial enzymatic electrochemistry. Fundamentals of bioelectrochemistry are discussed to allow others to integrate these techniques into their own research. More information can be found in the Review Article by Dylan G. Boucher and co-workers (10.1002/celc.202500287).

Combining Cu with CO-producing Ag is a promising strategy to improve the selectivity of a CO₂ reduction catalyst. However, the influence of the spatial distribution of the two metals is challenging to investigate. A synthesis route to deposit Cu either on top of a templated porous Ag electrode using sputter coating or inside the porous Ag structure using electrodeposition is presented. The Cu location is confirmed using advanced microscopy images, showing that for the electrodes with electrodeposited Cu, the interfacial area between Cu and Ag is higher. Catalytic testing demonstrates increased C₂₊ production, a lower H₂ selectivity, and higher ethanol-to-ethylene ratio for all bimetallic electrodes than for monometallic Cu or Ag catalysts. This is possibly due to CO spillover from Ag to Cu, electronic interaction between the two metals, or a higher local pH inside the Ag pores. Despite a significant loss of Cu, a high production of ethylene and ethanol is maintained over 6 h of electrolysis. Thus, engineering porous bimetallic electrodes provides an effective strategy to improve the ethylene and ethanol activity and selectivity of Cu-based catalysts.

The peculiar properties of electroactive polymers mark them as protagonists in the bioelectronic research field, with application in point-of-care devices, wearable electronics, neuroscience, cell biology, and more. They have been successfully employed for the design of both sensing and actuating interfaces, which exert complementary functions but benefit from common electrochemical mechanisms unique to these materials. The question is: to what extent sensing and actuating capabilities can be integrated within a single electrochemical transducer? The simultaneous pH detection and pH-controlled release of a model dye are investigated using screen-printed textiles for wearable applications. The transducer is based on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and is specifically functionalized to create a two-terminal pH sensor and subsequently loaded with the anionic dye. Simultaneous pH sensing and controlled dye release into the electrolytic solution are demonstrated via electrical and spectrophotometric techniques, while the local release of the dye is confirmed through scanning electrochemical microscopy. The findings confirm that the acquisition of a quantitative analytical signal and the release of the dye do not interfere with each other and can take place simultaneously at the same electrochemical interface. This opens new perspectives for the development of hybrid sensing and drug delivery systems.