Electrochemical Utilization Research Articles

Ultra-Low Loaded Platinum Via Plasma-Enhanced Atomic Layer Deposition for the Fuel Electrode Active Layer in Steam Reversible Solid Oxide Cells

Reversible solid oxide cells (rSOCs) are crucial energy devices in sustainable energy systems, offering efficient energy conversion and storage solutions through hydrogen. Conventional SOFC/SOEC operating temperatures are above 700°C; at these temperatures, the cells benefit from high energy conversion efficiencies due to facilitated electrochemical reactions and effective waste heat utilization. Despite their advantages, commercial rSOCs face hurdles including suboptimal performance in the intermediate temperature range of 500-700°C, limited lifespan, and elevated operational costs. Addressing these issues, significant progress has been made in electrode fabrication, particularly through advanced semiconductor fabrication methods such as atomic layer deposition (ALD). In this study, we explore the application of plasma-enhanced ALD (PEALD) for depositing exceptionally low loadings of platinum on Ni-yttria stabilized zirconia (Ni-YSZ) fuel electrodes, aiming to enhance both performance and stability. Employing this novel approach, we achieved precise control over the Pt nanoparticle deposition process, resulting in a catalyst loading of only 0.2 µg/cm2. Experimental results demonstrated that rSOC samples with 10 cycles of PEALD Pt exhibited a 20% increase in maximum power density (548 vs. 479 mW/cm2 at 700°C) and an 18% increase in current density (1260 vs. 1070 mA/cm2 at 1.5 V) compared to the bare samples. Notably, these improvements were achieved without any observable performance degradation over 50 hours of operation at 700°C with 50% humidified hydrogen. Density functional theory (DFT) simulations were employed to elucidate the mechanisms contributing to the enhanced activity, revealing that the nano-scale Pt deposition promotes efficient hydrogen oxidation and evolution reactions. These findings highlight the potential of PEALD for rSOC manufacturing, enabling the creation of highly active and stable electrodes with minimal precious metal loading. The outcomes of this study suggest that such advancements could lead to more economically viable and sustainable hydrogen energy solutions, aligning with broader goals of energy security and environmental sustainability. This work provides a compelling case for the wider application of nano-engineered catalysts in high-performance electrochemical systems at intermediate temperature ranges.

Electrochemical Sensors in the Food Sector: A Review.

In a world that is becoming increasingly concerned with health, safety, and the sustainability of food supply chains, the control and assurance of food quality have become of utmost importance. This review examines the application and potential of electrochemical sensors in the dynamic field of food science to meet these expanding demands. The article introduces electrochemical sensors and describes their operational mechanics and the components contributing to their function. A summary of the most prevalent electrochemical methods outlines the diverse food analysis techniques available. The review shifts to discussing the food science applications of these sensors, highlighting their crucial role in detecting compounds in food samples like meat, fish, juice, and milk for contemporary quality control. This paper showcases electrochemical sensors' utility in food analysis, underscoring their significance as powerful, efficient tools for maintaining food safety and how they could transform our approach to global food quality control and assurance.

A Perspective on Electrochemical Point Source Utilization of CO2 and Other Flue Gas Components to Value Added Chemicals.

Electrochemical CO2 reduction reaction (eCO2RR) has been explored extensively for mitigation of noxious CO2 gas generating C1 and C2+ hydrocarbons and oxygenates as value-added fuels and chemicals with remarkable selectivity. The source of CO2 being a pure CO2 feed, it does not fully satisfy the real-time digestion of industrial exhausts. Besides the detrimental effect of noxious gas mixture leading to global warming, there is a huge capital investment in purifying the flue gas mixtures from industries. The presence of other impurity gases affects the eCO2RR mechanism and its activity and selectivity toward C2+ products dwindle drastically. Impurities like NOx, SOx, O2, N2, and halide ions present in flue gas mixture reduce the conversion and selectivity of eCO2RR significantly. Instead of wiping out these impurities via separation processes, new strategies from material chemistry and electrochemistry can open new avenues for turning foes to friends! In this perspective, the co-electroreduction will vividly discussed and supporting role of different heteroatom-containing impurity gases with CO2, generating highly stable C─N, C─S, C─X bonds, and highlight the existing limitations and providing probable solutions for attaining further success in this field and translating this to industrial exhaust streams.

Enhanced performance of Lithium–Sulfur cells via novel nano-sized iron-plated sulfur composites

Lithium–sulfur cells are promising energy-storage systems because of their high energy density and the desirable electrochemical utilization rates of cost-effective sulfur cathodes. However, the commercialization of high-performance lithium–sulfur cells, which are characterized by a high discharge capacity and cyclic stability, necessitates simultaneous optimization of both the cell-fabrication parameters and cell-performance values. Here, we introduce a novel iron-plated sulfur composite featuring nano-sized conductive iron plating applied to micro-sized insulating sulfur particles through an innovative electroless-iron plating method. The iron-plated sulfur composite facilitates the realization of a lean-electrolyte lithium–sulfur cell at a low electrolyte-to-sulfur ratio of 5 μL mg−1, enabling high-loading sulfur cathodes (sulfur loadings of 10–14 mg cm−2) to attain a reversible discharge capacity (945–1033 mAh g−1) and a cycle life of 400 cycles. These well-controlled cell-fabrication parameters, coupled with the high cell performance, result in improved performance metrics, such as high areal capacity (10–13 mAh cm−2), improved energy density (22–28 mWh cm−2), and a low electrolyte-to-capacity ratio (4.8 μL mAh−1). These advancements are attributable to the incorporation of plated nano-sized iron, which endows the cathode with rapid electron/ion transfer, robust polysulfide retention, and heightened electrocatalysis capabilities for conversion-type battery chemistry.

Concept of Utilizing Ionic Liquids for the Co‐Electroreduction of Carbon Dioxide and Nitrogen‐Containing Compounds

AbstractFormation of C−N bonds through the electrochemical utilization of CO2 and nitrogen containing compounds (N‐compounds) is appealing for the purpose of converting waste and readily available sources or pollutants into value added chemicals at ambient conditions. Existing research predominantly explores these electrochemical reactions independently, often in aqueous electrolytes, leading to challenges associated with competitive hydrogen evolution reaction (HER), low product selectivity, and yield. Functional electrolytes such as those containing ionic liquids (ILs) present selective solubility to the solute reactants and present unique interactions with the electrode surface that can suppress the undesired side reactions such as HER while simultaneously co‐catalyzing the conversion of CO2 and N‐compounds such as N2, NO, NO2, and NO3. In this concept paper, we discuss how the microenvironment enabled by ILs can be leveraged to stabilize reaction intermediates at the electrode‐electrolyte interface, thereby promoting C−N bond formation on an active electrode surface at reduced overpotential, with the case study of CO2 and N‐compounds co‐catalysis to generate urea.

Enzymatic CO2 reduction catalyzed by natural and artificial Metalloenzymes

The continuously increasing level of atmospheric CO2 in the atmosphere has led to global warming. Converting CO2 into other carbon compounds could mitigate its atmospheric levels and produce valuable products, as CO2 also serves as a plentiful and inexpensive carbon feedstock. However, the inert nature of CO2 poses a major challenge for its reduction. To meet the challenge, nature has evolved metalloenzymes using transition metal ions like Fe, Ni, Mo, and W, as well as electron-transfer partners for their functions. Mimicking these enzymes, artificial metalloenzymes (ArMs) have been designed using alternative protein scaffolds and various metallocofactors like Ni, Co, Re, Rh, and FeS clusters. Both the catalytic efficiency and the scope of CO2-reduction product of these ArMs have been improved over the past decade. This review first focuses on the natural metalloenzymes that directly reduce CO2 by discussing their structures and active sites, as well as the proposed reaction mechanisms. It then introduces the common strategies for electrochemical, photochemical, or photoelectrochemical utilization of these native enzymes for CO2 reduction and highlights the most recent advancements from the past five years. We also summarize principles of protein design for bio-inspired ArMs, comparing them with native enzymatic systems and outlining challenges and opportunities in enzymatic CO2 reduction.

Grain boundary engineering: An emerging pathway toward efficient electrocatalysis

AbstractElectrochemical transformation processes involving carbon, hydrogen, oxygen, nitrogen, and small‐molecule chemistries represent a promising means to store renewable energy sources in the form of chemical energy. However, their widespread deployment is hindered by a lack of efficient, selective, durable, and affordable electrocatalysts. Recently, grain boundary (GB) engineering as one category of defect engineering, has emerged as a viable and powerful pathway to achieve improved electrocatalytic performances. This review presents a timely and comprehensive overview of recent advances in GB engineering for efficient electrocatalysis. The beneficial effects of introducing GBs into electrocatalysts are discussed, followed by an overview of the synthesis and characterization of GB‐enriched electrocatalysts. Importantly, the latest developments in leveraging GB engineering for enhanced electrocatalysis are thoroughly examined, focusing on the electrochemical utilization cycles of carbon, hydrogen, oxygen, and nitrogen. Future research directions are proposed to further advance the understanding and application of GB engineering for improved electrocatalysis.image

Superior Anodic Lithium Storage in Core–Shell Heterostructures Composed of Carbon Nanotubes and Schiff‐Base Covalent Organic Frameworks

Covalent organic frameworks (COFs) after undergoing the superlithiation process promise high‐capacity anodes while suffering from sluggish reaction kinetics and low electrochemical utilization of redox‐active sites. Herein, integrating carbon nanotubes (CNTs) with imine‐linked covalent organic frameworks (COFs) was rationally executed by in‐situ Schiff‐base condensation between 1,1′‐biphenyl]‐3,3′,5,5′‐tetracarbaldehyde and 1,4‐diaminobenzene in the presence of CNTs to produce core–shell heterostructured composites (CNT@COF). Accordingly, the redox‐active shell of COF nanoparticles around one‐dimensional conductive CNTs synergistically creates robust three‐dimensional hybrid architectures with high specific surface area, thus promoting electron transport and affording abundant active functional groups accessible for electrochemical utilization throughout the whole electrode. Remarkably, upon the full activation with a superlithiation process, the as‐fabricated CNT@COF anode achieves a specific capacity of 2324 mAh g−1, which is the highest specific capacity among organic electrode materials reported so far. Meanwhile, the superior rate capability and excellent cycling stability are also obtained. The redox reaction mechanisms for the COF moiety were further revealed by Fourier‐transform infrared spectroscopy in conjunction with X‐ray photoelectron spectroscopy, involving the reversible redox reactions between lithium ions and C=N groups and gradual electrochemical activation of the unsaturated C=C bonds within COFs.

Understanding the supercapacitive properties and charge storage dynamics of MnCo2S4 bimetallic sulfide electrodes synthesized via a single-step hydrothermal process

A recent study delves into the enhancement of supercapacitors to increase their energy density while maintaining fast charge-discharge capabilities and longevity. This is achieved by developing electrode materials with improved conductivity and carefully designed nanostructures to overcome the limitations of pseudocapacitors. The study highlights MnCo2S4 for its impressive specific capacitance and cost-effectiveness. It elucidates the synergistic interactions and charge transfer dynamics between manganese (Mn) and cobalt (Co), which significantly enhance electrochemical performance. A new one-step hydrothermal synthesis method is presented for producing MnCo2S4 nanogranules directly on a nickel foam substrate, eliminating the need for binders and achieving an optimized morphology that boosts electrochemical activity. Through a thorough analysis involving X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM) along with cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS), the study comprehensively characterizes the structural, morphological, and electrochemical properties of MnCo2S4. The synthesized MnCo2S4 electrode exhibited an outstanding capacitance of 6375 mF/cm2 at a current density of 25 mA/cm2. This exceptional performance is mainly attributed to its well-designed 3-D nanogranular structure, which not only enhances the accessibility of electrolyte ions to active sites, thus improving electrochemical reactivity and capacitive utilization, but also utilizes the synergistic interaction between manganese and cobalt. This synergy promotes enhanced redox reactions and stability, resulting in a higher specific capacitance and energy density. These results highlight the crucial role of advanced electrode material development and creative synthesis methods in advancing supercapacitors as a viable energy storage solution, demonstrating the groundbreaking potential of MnCo2S4 in electrochemical energy storage progress.

Challenges and Advancements in the Electrochemical Utilization of Ammonia Using Solid Oxide Fuel Cells.

Solid oxide fuel cells utilized with NH3 (NH3-SOFCs) have great potential to be environmentally friendly devices with high efficiency and energy density. The advancement of this technology is hindered by the sluggish kinetics of chemical or electrochemical processes occurring on anodes/catalysts. Extensive efforts have been devoted to developing efficient and durable anode/catalysts in recent decades. Although modifications to the structure, composition, and morphology of anodes or catalysts are effective, the mechanistic understandings of performance improvements or degradations remain incompletely understood. This review informatively commences by summarizing existing reports on the progress of NH3-SOFCs. It subsequently outlines the influence of factors on the performance of NH3-SOFCs. The degradation mechanisms of the cells/systems are also reviewed. Lastly, the persistent challenges in designing highly efficient electrodes/catalysts for low-temperature NH3-SOFCs, and future perspectives derived from SOFCs are discussed. Notably, durability, thermal cycling stability, and power density are identified as crucial indicators for enhancing low-temperature (550°C or below) NH3-SOFCs. This review aims to offer an updated overview of how catalysts/electrodes affect electrochemical activity and durability, offering critical insights for improving performance and mechanistic understanding, as well as establishing the scientific foundation for the design of electrodes for NH3-SOFCs.

Solid Electrolytes for Low-Temperature Carbon Dioxide Valorization: A Review.

One of the most promising approaches to address the global challenge of climate change is electrochemical carbon capture and utilization. Solid electrolytes can play a crucial role in establishing a chemical-free pathway for the electrochemical capture of CO2. Furthermore, they can be applied in electrocatalytic CO2 reduction reactions (CO2RR) to increase carbon utilization, produce high-purity liquid chemicals, and advance hybrid electro-biosystems. This review article begins by covering the fundamentals and processes of electrochemical CO2 capture, emphasizing the advantages of utilizing solid electrolytes. Additionally, it highlights recent advancements in the use of the solid polymer electrolyte or solid electrolyte layer for the CO2RR with multiple functions. The review also explores avenues for future research to fully harness the potential of solid electrolytes, including the integration of CO2 capture and the CO2RR and performance assessment under realistic conditions. Finally, this review discusses future opportunities and challenges, aiming to contribute to the establishment of a green and sustainable society through electrochemical CO2 valorization.

Revisit of Polyaniline as a High-Capacity Organic Cathode Material for Li-Ion Batteries.

Polyaniline (PANI) has long been explored as a promising organic cathode for Li-ion batteries. However, its poor electrochemical utilization and cycling instability cast doubt on its potential for practical applications. In this work, we revisit the electrochemical performance of PANI in nonaqueous electrolytes, and reveal an unprecedented reversible capacity of 197.2 mAh g-1 (244.8 F g-1) when cycled in a wide potential range of 1.5 to 4.4 V vs. Li+/Li. This ultra-high capacity derives from 70% -NH- transformed to =NH+- during deep charging/discharging process. This material also demonstrates a high average coulombic efficiency of 98%, an excellent rate performance with 73.5 mAh g-1 at 1800 mA g-1, and retains 76% of initial value after 100 cycles, which are among the best reported values for PANI electrodes in battery applications.

Special issue on electrochemical conversion and utilization of hydrogen energy

Special issue on electrochemical conversion and utilization of hydrogen energy

Synergy effect of polyaspartic acid and D-phenylalanine on corrosion inhibition caused by Desulfovibrio vulgaris

Microbiologically influenced corrosion (MIC) poses a threat to various fields, particularly in piping and cooling water systems. As a green corrosion inhibitor, polyaspartic acid (PASP) faces challenges in achieving the intended corrosion inhibition against MIC due to biofilm. Therefore, mitigating biofilm might be the key to improving the corrosion inhibition of PASP. D-Phenylalanine (D-Phe) was selected as an enhancer to promote the inhibition of PASP on MIC caused by Desulfovibrio vulgaris due to its potential role in biofilm formation in this work. The joint application of PASP and D-Phe reduced the corrosion rate by 76.54% and obviously decreased the depth of corrosion pits with the maximum depth at 0.95 µm. Also, fewer cells adhered to the coupon surface due to the combined action of PASP and D-Phe, leading to thin and loose biofilm. Besides, both cathodic and anodic reactions were retarded with PASP and D-Phe, resulting in a low corrosion current at 0.530 × 10−7 A/cm2. The primary synergy mechanism is that D-Phe promoted the formation of PASP protective film via decreasing bacterial adhesion and thus inhibited electrochemical reaction and electron utilization of cells from metal surface. This study introduces a novel strategy to augment the effectiveness of PASP in inhibiting MIC.

Cement/Sulfur for Lithium-Sulfur Cells.

Lithium-sulfur batteries represent a promising class of next-generation rechargeable energy storage technologies, primarily because of their high-capacity sulfur cathode, reversible battery chemistry, low toxicity, and cost-effectiveness. However, they lack a tailored cell material and configuration for enhancing their high electrochemical utilization and stability. This study introduces a cross-disciplinary concept involving cost-efficient cement and sulfur to prepare a cement/sulfur energy storage material. Although cement has low conductivity and porosity, our findings demonstrate that its robust polysulfide adsorption capability is beneficial in the design of a cathode composite. The cathode composite attains enhanced cell fabrication parameters, featuring a high sulfur content and loading of 80 wt% and 6.4 mg cm-2, respectively. The resulting cell with the cement/sulfur cathode composite exhibits high active-material retention and utilization, resulting in a high charge storage capacity of 1189 mA∙h g-1, high rate performance across C/20 to C/3 rates, and an extended lifespan of 200 cycles. These attributes contribute to excellent cell performance values, demonstrating areal capacities ranging from 4.59 to 7.61 mA∙h cm-2, an energy density spanning 9.63 to 15.98 mW∙h cm-2, and gravimetric capacities between 573 and 951 mA∙h g-1 per electrode. Therefore, this study pioneers a new approach in lithium-sulfur battery research, opting for a nonporous material with robust polysulfide adsorption capabilities, namely cement. It effectively showcases the potential of the resulting cement/sulfur cathode composite to enhance fabrication feasibility, cell fabrication parameters, and cell performance values.

Effect of cerium dioxide on the anode performance of aluminum-air batteries

In this word, the effects of adding different contents of CeO2 to pure Al anode alloy plates on the anode performance of aluminum air batteries were evaluated using an electrochemical workstation, a blue dot test system, and scanning electron microscopy (SEM). The results showed that the addition of CeO2 had a positive effect on the discharge performance of aluminum anodes for aluminum-air batteries, especially at high current density of 100 mA·cm−2 for Al-0.20 wt% CeO2 and Al-0.25 wt% CeO2 anodes, and also improved the electrochemical activity, corrosion resistance, and anode utilization of aluminum anodes.

Review on CO2 Management: From CO2 Sources, Capture, and Conversion to Future Perspectives of Gas-Phase Electrochemical Conversion and Utilization

Review on CO₂ Management: From CO₂ Sources, Capture, and Conversion to Future Perspectives of Gas-Phase Electrochemical Conversion and Utilization

Recent research progresses of Sn/Bi/In-based electrocatalysts for electroreduction CO2 to formate.

Carbon dioxide electroreduction reaction (CO2RR) can take full advantage of sustainable power to reduce the continuously increasing carbon emissions. Recycling CO2 to produce formic acid or formate is a technologically and economically viable route to accomplish CO2 cyclic utilization. Developing efficient and cost-effective electrocatalysts with high selectivity towards formate is prioritized for the industrialized applications of CO2RR electrolysis. From the previous explored CO2RR catalysts, Sn, Bi and In based materials have drawn increasing attentions due to the high selectivity towards formate. However, there are still confronted with several challenges for the practical applications of these materials. Therefore, a rational design of the catalysts for formate is urgently needed for the target of industrialized applications. Herein, we comprehensively summarized the recent development in the advanced electrocatalysts for the CO2RR to formate. Firstly, the reaction mechanism of CO2RR is introduced. Then the preparation and design strategies of the highly active electrocatalysts are presented. Especially the innovative design mechanism in engineering materials for promoting catalytic performance, and the efforts on mechanistic exploration using in situ (ex situ) characterization techniques are reviewed. Subsequently, some perspectives and expectations are proposed about current challenges and future potentials in CO2RR research.

Integrated Electrochemical Carbon Capture and Utilization by Redox‐Active Amine Grafted Gold Nanoparticles

AbstractElectrochemical carbon capture and utilization (eCCU) from flue gas CO2 could avoid high energy consumption and capital input in conventional capture, storage, and utilization, which is a promising approach for achieving negative emissions and producing “e‐chemicals.” However, low CO2 concentration and leftover O2 in the flue gas presumably lowers the eCCU performance. Herein, redox‐active 2‐amino‐5‐mercapto‐1,3,4‐thiadiazole (AMT) functionalized gold nanoparticles are synthesized to achieve integrated electrochemical capture and reduction of CO2 in simulated flue gas (SFG, 15% CO2, 4% O2, balanced with N2), achieving maximum CO Faradaic efficiency of 80.2% at −0.45 V versus RHE in H‐type cell, and 66.0% at voltage of 2.7 V in a full cell, respectively. The AMT ligand can capture CO2 by strong interaction with CO2 in the reduced state and serve as a selective layer to suppress O2 reduction, which provides the ability of electrochemical carbon capture from SFG and significantly decreases energy required for CO2 electro‐reduction.

Operando Fe dissolution in Fe-N-C electrocatalysts during acidic oxygen reduction: impact of local pH change.

Atomic Fe in N-doped C (Fe-N-C) catalysts provide the most promising non-precious metal O2 reduction activity at the cathodes of proton exchange membrane fuel cells. However, one of the biggest remaining challenges to address towards their implementation in fuel cells is their limited durability. Fe demetallation has been suggested as the primary initial degradation mechanism. However, the fate of Fe under different operating conditions varies. Here, we monitor operando Fe dissolution of a highly porous and >50% FeN x electrochemical utilization Fe-N-C catalyst in 0.1 M HClO4, under O2 and Ar at different temperatures, in both flow cell and gas diffusion electrode (GDE) half-cell coupled to inductively coupled plasma mass spectrometry (ICP-MS). By combining these results with pre- and post-mortem analyses, we demonstrate that in the absence of oxygen, Fe cations diffuse away within the liquid phase. Conversely, at -15 mA cm-2 geo and more negative O2 reduction currents, the Fe cations reprecipitate as Fe-oxides. We support our conclusions with a microkinetic model, revealing that the local pH in the catalyst layer predominantly accounts for the observed trend. Even at a moderate O2 reduction current density of -15 mA cm-2 geo at 25 °C, a significant H+ consumption and therefore pH increase (pH = 8-9) within the bulk Fe-N-C layer facilitate precipitation of Fe cations. This work provides a unified view on the Fe dissolution degradation mechanism for a model Fe-N-C in both high-throughput flow cell and practical operating GDE conditions, underscoring the crucial role of local pH in regulating the stability of the active sites.