To understand the physical meaning of each resistance in an electrode-supported solid oxide cell (ECS), a complex nonlinear least-square (CNLS) equivalent circuit was developed. The commercial type of ECS measured their electrochemical properties in various gas compositions (oxygen, hydrogen, and water vapor) and temperature. The obtained impedance spectra were analyzed using the distribution of relaxation times (DRT) method to deconvolute the resistance of the cell. Subsequently, the developed CNLS equivalent circuit was used to provide the physical meaning of each resistance. R-CPE was used to analyze gas conversion resistance, Warburg impedance was used to analyze gas diffusion at a very-low-frequency region, and Gerischer impedance was used to analyze electrode resistance. Finally, the model was validated by comparing the transport properties of the electrode obtained from the model with the reported data. Therefore, the developed model could aid in understanding the physical meaning of each resistance of the cell.
{"title":"Elucidating Reaction Resistances in Electrode-Supported Solid Oxide Cells Using a Nonlinear Least-Square Model","authors":"Rikuto Konishi, Riyan Achmad Budiman, Marika Sakai, Mina Yamaguchi, Tatsuya Kawada, Keiji Yashiro","doi":"10.1016/j.electacta.2025.146289","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146289","url":null,"abstract":"To understand the physical meaning of each resistance in an electrode-supported solid oxide cell (ECS), a complex nonlinear least-square (CNLS) equivalent circuit was developed. The commercial type of ECS measured their electrochemical properties in various gas compositions (oxygen, hydrogen, and water vapor) and temperature. The obtained impedance spectra were analyzed using the distribution of relaxation times (DRT) method to deconvolute the resistance of the cell. Subsequently, the developed CNLS equivalent circuit was used to provide the physical meaning of each resistance. <em>R-CPE</em> was used to analyze gas conversion resistance, <em>Warburg</em> impedance was used to analyze gas diffusion at a very-low-frequency region, and <em>Gerischer</em> impedance was used to analyze electrode resistance. Finally, the model was validated by comparing the transport properties of the electrode obtained from the model with the reported data. Therefore, the developed model could aid in understanding the physical meaning of each resistance of the cell.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"138 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-23DOI: 10.1016/j.electacta.2025.146288
Crystal Thompson, Elizabeth Tonsel-White, Alvin A. Holder, Colin D. McMillen, Mark A.W. Lawrence
Six copper(II) pincer complexes of κ3-SNS, ONS, SNN or ONN coordination modes were investigated as electrocatalysts for the hydrogen evolution reaction (HER) in dimethylformamide using acetic acid and trifluoroacetic acid as proton sources. The copper(II) complexes of general formula [Cu(Ln)(OAc)]•zH2O (z = 0-3) and Ln = bis-N-(4-chlorophenyl)pyridine-2,6-dicarbothioamide (L1), bis-N-(2,5-dimethoxyphenyl)pyridine-2,6-dicarbothioamide (L2), N-(2,5-dimethoxyphenyl)-6-[(2,5-dimethoxyphenyl)carbamothioyl]pyridine-2-carboxamide (L3), 6-(6-chloro-1,3-benzothiazol-2-yl)-N-(4-chlorophenyl)pyridine-2-carbothioamide (L4), 6-(4,7-dimethoxy-2-benzothiazoyl)-N-(2,5-dimethoxyphenyl)-pyridinecarboxamide (L5) and 6-(4,7-dimethoxy-2-benzothiazolyl)-N-(2,5-dimethoxyphenyl)-2-pyridinecarbothioamide (L6), were prepared by refluxing Cu(OAc)2•H2O with Ln in ethanol. The copper complexes with the κ3-SNS coordination mode showed the highest catalytic enhancement and Faradaic efficiencies. The results also suggested that the methoxy substituents were slightly advantageous to the chloro substituent. Moderate overpotentials between 0.69 and 0.83 V at Faradaic yields between 77 and 97% were obtained for the Cu(II) complexes in acetic acid. Lower overpotentials within the range of 0.57 and 0.73 V were obtained at Faradaic yields between 86 and 98% when trifluoroacetic acid was used as the proton source. Rate constants were extracted from foot-of-the-wave analysis (FOWA) plots where an EECC mechanism is proposed for the catalytic formation of H2.
{"title":"Electrocatalytic hydrogen evolution with copper(II) pincer complexes bearing functionalized pyridyl benzothiazoles and carbo(thio)amides of a κ3-SNS, ONS, SNN or ONN coordination mode","authors":"Crystal Thompson, Elizabeth Tonsel-White, Alvin A. Holder, Colin D. McMillen, Mark A.W. Lawrence","doi":"10.1016/j.electacta.2025.146288","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146288","url":null,"abstract":"Six copper(II) pincer complexes of κ<sup>3</sup>-SNS, ONS, SNN or ONN coordination modes were investigated as electrocatalysts for the hydrogen evolution reaction (HER) in dimethylformamide using acetic acid and trifluoroacetic acid as proton sources. The copper(II) complexes of general formula [Cu(<strong><em>L<sup>n</sup></em></strong>)(OAc)]•zH<sub>2</sub>O (z = 0-3) and <strong><em>L</em><sup>n</sup></strong> = bis-<em>N</em>-(4-chlorophenyl)pyridine-2,6-dicarbothioamide (<strong><em>L<sup>1</sup></em></strong>), bis-<em>N</em>-(2,5-dimethoxyphenyl)pyridine-2,6-dicarbothioamide (<strong><em>L</em><sup>2</sup></strong>), <em>N</em>-(2,5-dimethoxyphenyl)-6-[(2,5-dimethoxyphenyl)carbamothioyl]pyridine-2-carboxamide (<strong><em>L</em><sup>3</sup></strong>), 6-(6-chloro-1,3-benzothiazol-2-yl)-<em>N</em>-(4-chlorophenyl)pyridine-2-carbothioamide (<strong><em>L</em><sup>4</sup></strong>), 6-(4,7-dimethoxy-2-benzothiazoyl)-<em>N</em>-(2,5-dimethoxyphenyl)-pyridinecarboxamide (<strong><em>L</em><sup>5</sup></strong>) and 6-(4,7-dimethoxy-2-benzothiazolyl)-<em>N</em>-(2,5-dimethoxyphenyl)-2-pyridinecarbothioamide (<strong><em>L<sup>6</sup></em></strong>), were prepared by refluxing Cu(OAc)<sub>2</sub>•H<sub>2</sub>O with <strong><em>L</em><sup>n</sup></strong> in ethanol. The copper complexes with the κ<sup>3</sup>-SNS coordination mode showed the highest catalytic enhancement and Faradaic efficiencies. The results also suggested that the methoxy substituents were slightly advantageous to the chloro substituent. Moderate overpotentials between 0.69 and 0.83 V at Faradaic yields between 77 and 97% were obtained for the Cu(II) complexes in acetic acid. Lower overpotentials within the range of 0.57 and 0.73 V were obtained at Faradaic yields between 86 and 98% when trifluoroacetic acid was used as the proton source. Rate constants were extracted from foot-of-the-wave analysis (FOWA) plots where an EECC mechanism is proposed for the catalytic formation of H<sub>2</sub>.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"13 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-23DOI: 10.1016/j.electacta.2025.146293
M.A. Deyab, Omnia A.A. El-Shamy, Laurent Ruhlmann, Emad E. El-Katori
This study presents an evaluation of the FCNTs@CoS2 composite for supercapacitor applications through a comprehensive analysis involving theoretical computations and electrochemical measurements (cycle voltammetry, or CV, and galvanostatic charge-discharge, or GSCD). The structural characteristics and morphology of the synthesized FCNTs@CoS2 composites were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). The performance of the composite is compared to pure CoS2, revealing a substantial improvement in specific capacitance. At 1 A g−1, the specific capacitances of CoS2 and FCNTs@CoS2 electrodes are measured at 197 F g−1 and 493 F g−1, respectively, highlighting the superior performance of the composite. Furthermore, the FCNTs@CoS2 electrode demonstrates exceptional stability, retaining 91.2% of its capacity after 4000 cycles, in contrast to the CoS2 electrode's 64.9% retention after 3000 cycles. These results underscore the remarkable potential of the FCNTs@CoS2 composite as a high-performance and long-lasting material for supercapacitor electrodes, promising advancements in energy storage technology.
{"title":"FCNTs@CoS2 composite for supercapacitor applications: electrochemical measurements and theoretical calculations","authors":"M.A. Deyab, Omnia A.A. El-Shamy, Laurent Ruhlmann, Emad E. El-Katori","doi":"10.1016/j.electacta.2025.146293","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146293","url":null,"abstract":"This study presents an evaluation of the FCNTs@CoS<sub>2</sub> composite for supercapacitor applications through a comprehensive analysis involving theoretical computations and electrochemical measurements (cycle voltammetry, or CV, and galvanostatic charge-discharge, or GSCD). The structural characteristics and morphology of the synthesized FCNTs@CoS<sub>2</sub> composites were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). The performance of the composite is compared to pure CoS<sub>2</sub>, revealing a substantial improvement in specific capacitance. At 1 A g<sup>−1</sup>, the specific capacitances of CoS<sub>2</sub> and FCNTs@CoS<sub>2</sub> electrodes are measured at 197 F g<sup>−1</sup> and 493 F g<sup>−1</sup>, respectively, highlighting the superior performance of the composite. Furthermore, the FCNTs@CoS<sub>2</sub> electrode demonstrates exceptional stability, retaining 91.2% of its capacity after 4000 cycles, in contrast to the CoS<sub>2</sub> electrode's 64.9% retention after 3000 cycles. These results underscore the remarkable potential of the FCNTs@<sub>CoS2</sub> composite as a high-performance and long-lasting material for supercapacitor electrodes, promising advancements in energy storage technology.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"24 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-23DOI: 10.1016/j.electacta.2025.146287
Zixuan Zhang, Chang Li, Pengbo Ding, Lixiu Guan, Zhuoao Li, Shuo Zhang, Dan Xing, Junguang Tao
The quest for high-performance supercapacitors with enhanced energy density and cycling stability poses a significant challenge in sustainable energy storage. In this study, we engineered a hybrid material combining amorphous domains to facilitate rapid ion diffusion with crystalline phases of CoNiO2 and Ni(OH)2 to enhance electronic conductivity. Remarkably, when exposed to magnetic fields, it demonstrated a 23.9% capacity increase (from 709.3 to 879.1 C g-1), attributed to magnetohydrodynamic effects that enhance OH- ion transport and reduce charge recombination. At 15 A g-1, the device retained 81.9% of its capacity at 1 A g-1. Magnetic fields were found to lower charge-transfer resistance (from 0.743 to 0.481 Ω at 100 mT) and promote diffusion-controlled contributions via Lorentz force-driven ion convection. In asymmetric supercapacitor configurations, the device achieved 41.00 Wh kg-1 at 937.4 W kg-1 without a magnetic field. At 200 mT, it delivered 44.38 Wh kg-1 at 926.7 W kg-1, with 96.2% capacity retention after 20,000 cycles, demonstrating an enhanced energy storage performance. This work demonstrates a novel strategy for leveraging magnetic fields to address the conductivity-diffusivity trade-off in transition metal hydroxides, providing a universal strategy for developing high-energy storage systems in electromagnetically active environments.
寻求具有更高能量密度和循环稳定性的高性能超级电容器是可持续储能领域的一项重大挑战。在这项研究中，我们设计了一种混合材料，它将非晶态畴与 CoNiO2 和 Ni(OH)2 晶态相结合，前者可促进离子的快速扩散，后者可增强电子传导性。值得注意的是，当暴露在磁场中时，它的容量增加了 23.9%（从 709.3 C g-1 增加到 879.1 C g-1），这归功于磁流体动力学效应，它增强了 OH 离子传输并减少了电荷重组。在 15 A g-1 的条件下，该装置的容量保持了 1 A g-1 时的 81.9%。研究发现，磁场可降低电荷传输电阻（100 mT 时从 0.743 Ω 降至 0.481 Ω），并通过洛伦兹力驱动的离子对流促进扩散控制贡献。在非对称超级电容器配置中，该装置在没有磁场的情况下以 937.4 W kg-1 的功率实现了 41.00 Wh kg-1。在 200 mT 下，该装置能以 926.7 W kg-1 的功率输出 44.38 Wh kg-1，在 20,000 次循环后容量保持率为 96.2%，显示出更强的储能性能。这项工作展示了一种利用磁场解决过渡金属氢氧化物中电导率-扩散率权衡问题的新策略，为在电磁活跃环境中开发高能量存储系统提供了一种通用策略。
{"title":"Magnetic field-enhanced crystalline-amorphous hybrid nickel-cobalt hydroxide nanotubes for high-energy and 20,000-cycle stability in supercapacitors: mechanistic insights and performance enhancement","authors":"Zixuan Zhang, Chang Li, Pengbo Ding, Lixiu Guan, Zhuoao Li, Shuo Zhang, Dan Xing, Junguang Tao","doi":"10.1016/j.electacta.2025.146287","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146287","url":null,"abstract":"The quest for high-performance supercapacitors with enhanced energy density and cycling stability poses a significant challenge in sustainable energy storage. In this study, we engineered a hybrid material combining amorphous domains to facilitate rapid ion diffusion with crystalline phases of CoNiO<sub>2</sub> and Ni(OH)<sub>2</sub> to enhance electronic conductivity. Remarkably, when exposed to magnetic fields, it demonstrated a 23.9% capacity increase (from 709.3 to 879.1 C g<sup>-1</sup>), attributed to magnetohydrodynamic effects that enhance OH<sup>-</sup> ion transport and reduce charge recombination. At 15 A g<sup>-1</sup>, the device retained 81.9% of its capacity at 1 A g<sup>-1</sup>. Magnetic fields were found to lower charge-transfer resistance (from 0.743 to 0.481 Ω at 100 mT) and promote diffusion-controlled contributions via Lorentz force-driven ion convection. In asymmetric supercapacitor configurations, the device achieved 41.00 Wh kg<sup>-1</sup> at 937.4 W kg<sup>-1</sup> without a magnetic field. At 200 mT, it delivered 44.38 Wh kg<sup>-1</sup> at 926.7 W kg<sup>-1</sup>, with 96.2% capacity retention after 20,000 cycles, demonstrating an enhanced energy storage performance. This work demonstrates a novel strategy for leveraging magnetic fields to address the conductivity-diffusivity trade-off in transition metal hydroxides, providing a universal strategy for developing high-energy storage systems in electromagnetically active environments.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"67 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The interaction of calcium ions with gramicidin A (gA) ion channels represents a fundamental process with significant implications for understanding ion channel regulation in biological membranes. This study employs electrochemical impedance spectroscopy (EIS), surface-enhanced infrared absorption spectroscopy (SEIRAS), and Langmuir trough experiments to unravel the multifaceted mechanism of calcium-induced blockage of gA channels in a DOPC lipid bilayer. The findings reveal that calcium ions interact with the polar headgroups of DOPC lipids, inducing dehydration and increased packing density, which reduce the mobility of gramicidin monomers. Structural analysis highlights significant elongation of the gA helices, weakening of hydrogen bonds, and a shift in the conformational equilibrium towards inactive monomeric forms. These observations challenge the conventional view of calcium ion blockage being solely due to steric hindrance, proposing instead a broader mechanism involving alterations in both the membrane environment and peptide structure. This novel perspective on calcium-ion-induced ion channel modulation provides valuable insights for designing biomimetic systems and developing therapeutic strategies targeting ion channel dysfunction.
{"title":"Insight into the Mechanism of Calcium-Induced Blockage of Gramicidin A Ion Channels","authors":"Paria Pashazadeh Panahi, Damian Dziubak, Dorota Matyszewska, Mariusz Maciorowski, Sławomir Sęk","doi":"10.1016/j.electacta.2025.146292","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146292","url":null,"abstract":"The interaction of calcium ions with gramicidin A (gA) ion channels represents a fundamental process with significant implications for understanding ion channel regulation in biological membranes. This study employs electrochemical impedance spectroscopy (EIS), surface-enhanced infrared absorption spectroscopy (SEIRAS), and Langmuir trough experiments to unravel the multifaceted mechanism of calcium-induced blockage of gA channels in a DOPC lipid bilayer. The findings reveal that calcium ions interact with the polar headgroups of DOPC lipids, inducing dehydration and increased packing density, which reduce the mobility of gramicidin monomers. Structural analysis highlights significant elongation of the gA helices, weakening of hydrogen bonds, and a shift in the conformational equilibrium towards inactive monomeric forms. These observations challenge the conventional view of calcium ion blockage being solely due to steric hindrance, proposing instead a broader mechanism involving alterations in both the membrane environment and peptide structure. This novel perspective on calcium-ion-induced ion channel modulation provides valuable insights for designing biomimetic systems and developing therapeutic strategies targeting ion channel dysfunction.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1016/j.electacta.2025.146284
Nilüfer Çakmakcı Lee, Gyosik Kim, Jo Moon, Jihoon Ahn, Hosin Lee, Hyemin Kim, Junki Bang, Jiwon Sun, Ji Young Kim, Ki Yoon Bae, Samick Son, Kyoungmin Min, Youngjin Jeong
Anode-free solid-state batteries (AFSSBs) are regarded as a next-generation battery technology due to their high gravimetric/volumetric energy densities and safety. Recent studies suggested that AFSSBs require an interlayer between the current collector and solid-state electrolyte to prevent non-uniform flux and side reactions with deposited Li. Carbon nanotubes (CNTs) are effective interlayers thanks to their high Li-ion diffusivity, good chemical stability, and great mechanical strength. Nevertheless, a detailed understanding of the influence of CNT interlayer is crucial for advancing AFSSB research. Herein, the role of the CNT film interlayer on Li deposition was explored through elemental mapping analyses at various states of charge and molecular dynamics (MD) simulations. According to the results, the nano-porous CNT interlayer promotes uniform Li distribution, which improves the battery performance. Moreover, MD simulations indicate that Li atoms attach to the CNT bundles without significant aggregation, meaning that Li moves toward the current collector. It is assumed that Li diffusion through the interlayer during cycling is likely driven by two mechanisms, which are concentration gradient and electric field. This study is anticipated to serve as a foundational reference for future research on lithium diffusion in the interlayer in all-solid-state batteries (AFSSBs).
{"title":"Role of Carbon Nanotube Film Interlayer for Li-free All-Solid-State Battery","authors":"Nilüfer Çakmakcı Lee, Gyosik Kim, Jo Moon, Jihoon Ahn, Hosin Lee, Hyemin Kim, Junki Bang, Jiwon Sun, Ji Young Kim, Ki Yoon Bae, Samick Son, Kyoungmin Min, Youngjin Jeong","doi":"10.1016/j.electacta.2025.146284","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146284","url":null,"abstract":"Anode-free solid-state batteries (AFSSBs) are regarded as a next-generation battery technology due to their high gravimetric/volumetric energy densities and safety. Recent studies suggested that AFSSBs require an interlayer between the current collector and solid-state electrolyte to prevent non-uniform flux and side reactions with deposited Li. Carbon nanotubes (CNTs) are effective interlayers thanks to their high Li-ion diffusivity, good chemical stability, and great mechanical strength. Nevertheless, a detailed understanding of the influence of CNT interlayer is crucial for advancing AFSSB research. Herein, the role of the CNT film interlayer on Li deposition was explored through elemental mapping analyses at various states of charge and molecular dynamics (MD) simulations. According to the results, the nano-porous CNT interlayer promotes uniform Li distribution, which improves the battery performance. Moreover, MD simulations indicate that Li atoms attach to the CNT bundles without significant aggregation, meaning that Li moves toward the current collector. It is assumed that Li diffusion through the interlayer during cycling is likely driven by two mechanisms, which are concentration gradient and electric field. This study is anticipated to serve as a foundational reference for future research on lithium diffusion in the interlayer in all-solid-state batteries (AFSSBs).","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"43 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1016/j.electacta.2025.146283
Bapi Bera, Anirban Roy, Douglas S Aaron, Matthew M. Mench
In this study, tin (Sn) nanoparticles are demonstrated to effectively catalyze the reduction of CO2 to formate in an alkaline medium. Catalytically active Sn-based nanoparticles, supported on carbon black (Sn/C) and highly conductive graphene nanosheets (Sn/GN), present a promising approach to mitigating atmospheric CO2 emissions when integrated with capture technologies. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were employed to evaluate the prepared catalysts in CO2-saturated 0.5 M KHCO3 using a three-electrode rotating disk electrode (RDE) configuration. The results revealed a significantly lower charge-transfer resistance for graphene-supported tin compared to carbon black-supported tin. The CO2 reduction to formate was further demonstrated in a full electrochemical cell setup resembling the architecture of a low-temperature polymer electrolyte fuel cell (PEFC) operating in an alkaline medium with an anion exchange membrane (AEM). Performance tests were conducted with both triple-serpentine and parallel flow field architectures, showing flow rate-dependent behavior. Additionally, an ex-situ RDE technique was utilized to detect and quantify formate production during CO2 reduction in the full-cell configuration. This work highlights the importance of catalyst support materials and flow field design in optimizing CO2 electroreduction systems.
{"title":"Electroreduction of CO2 to formate on modified graphene-supported Sn nanoparticles","authors":"Bapi Bera, Anirban Roy, Douglas S Aaron, Matthew M. Mench","doi":"10.1016/j.electacta.2025.146283","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146283","url":null,"abstract":"In this study, tin (Sn) nanoparticles are demonstrated to effectively catalyze the reduction of CO<sub>2</sub> to formate in an alkaline medium. Catalytically active Sn-based nanoparticles, supported on carbon black (Sn/C) and highly conductive graphene nanosheets (Sn/GN), present a promising approach to mitigating atmospheric CO<sub>2</sub> emissions when integrated with capture technologies. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were employed to evaluate the prepared catalysts in CO<sub>2</sub>-saturated 0.5 M KHCO<sub>3</sub> using a three-electrode rotating disk electrode (RDE) configuration. The results revealed a significantly lower charge-transfer resistance for graphene-supported tin compared to carbon black-supported tin. The CO<sub>2</sub> reduction to formate was further demonstrated in a full electrochemical cell setup resembling the architecture of a low-temperature polymer electrolyte fuel cell (PEFC) operating in an alkaline medium with an anion exchange membrane (AEM). Performance tests were conducted with both triple-serpentine and parallel flow field architectures, showing flow rate-dependent behavior. Additionally, an ex-situ RDE technique was utilized to detect and quantify formate production during CO<sub>2</sub> reduction in the full-cell configuration. This work highlights the importance of catalyst support materials and flow field design in optimizing CO<sub>2</sub> electroreduction systems.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"17 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1016/j.electacta.2025.146286
Mohammad Furquan, Zahid Manzoor Bhat, Mohammad Qamar
Electrolyte formulation significantly impacts the electrochemical performance of redox flow batteries (RFBs) in an alkaline medium. We demonstrate that the voltage, reversibility, and galvanostatic cyclic stability of RFBs improve with a potassium hydroxide (KOH) concentration beyond 1 M (pH 14). The study shows that a high KOH concentration is more critical for catholyte-potassium ferrocyanide (PF) than anolyte-Alizarin to maintain high capacity retention in full-cell, confirmed via symmetric (x M KOH-Alizarin || x M KOH-PF) and asymmetric (x M KOH-Alizarin || y M KOH-PF) KOH concentrations. Asymmetric high KOH concentration (4 M KOH-Alizarin || 3 M KOH-PF) compared to conventional symmetric (1 M KOH-Alizarin || 1 M KOH-PF) exhibits higher discharge capacity retention (∼32%) after 200 cycles at 100% state of charge (SOC) with ∼5% higher energy efficiency at 30°C. Furthermore, our cyclic voltammetry experiments reveal that the separation (ΔE) between cathodic and anodic peaks decreases significantly with high KOH concentration at the graphite felt compared to the glassy carbon electrode, enhancing the redox couple's reversibility, therefore emphasizing its crucial role in the RFBs.
{"title":"Electrolyte engineering beyond the conventional alkaline concentration for high-capacity retention of aqueous redox flow batteries","authors":"Mohammad Furquan, Zahid Manzoor Bhat, Mohammad Qamar","doi":"10.1016/j.electacta.2025.146286","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146286","url":null,"abstract":"Electrolyte formulation significantly impacts the electrochemical performance of redox flow batteries (RFBs) in an alkaline medium. We demonstrate that the voltage, reversibility, and galvanostatic cyclic stability of RFBs improve with a potassium hydroxide (KOH) concentration beyond 1 M (pH 14). The study shows that a high KOH concentration is more critical for catholyte-potassium ferrocyanide (PF) than anolyte-Alizarin to maintain high capacity retention in full-cell, confirmed via symmetric (x M KOH-Alizarin || x M KOH-PF) and asymmetric (x M KOH-Alizarin || y M KOH-PF) KOH concentrations. Asymmetric high KOH concentration (4 M KOH-Alizarin || 3 M KOH-PF) compared to conventional symmetric (1 M KOH-Alizarin || 1 M KOH-PF) exhibits higher discharge capacity retention (∼32%) after 200 cycles at 100% state of charge (SOC) with ∼5% higher energy efficiency at 30°C. Furthermore, our cyclic voltammetry experiments reveal that the separation (ΔE) between cathodic and anodic peaks decreases significantly with high KOH concentration at the graphite felt compared to the glassy carbon electrode, enhancing the redox couple's reversibility, therefore emphasizing its crucial role in the RFBs.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"41 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1016/j.electacta.2025.146282
Xiaodong He, Xingjin Xiao, Yongxiang Guan, Xinshuang Cui
Understanding ion transport behaviors in confined ionic liquid (IL)/aqueous solution systems is crucial for advancing nanofluidic device applications. In this study, we investigate the ionic current behaviors of such systems using quartz nanopipettes, revealing significant ionic current rectification (ICR) phenomena at the nanoscale, which are absent at the microscale. Experimental results show that in the absence of an external bias voltage, diffusion currents in nanopipettes are negative due to the liquid-junction potential at the IL/aqueous interface. The rectification ratio (R) increases from 1.47 to 11.64 as the KCl electrolyte concentration increases from 0.01 M to 1 M, indicating a unique behavior distinct from conventional aqueous systems. Additionally, different ILs exhibit varying rectification strengths, following the sequence: [Bmim] [BF4]> [Bmim] [NTf2]> [Bmim] [PF6]> [Bmim] [N(CN)2]. To further elucidate the underlying mechanisms, we conducted finite element simulation using a Poisson-Nernst-Planck model. The simulation results further demonstrate that IL diffusion, electrostatic interactions, and electric double layer effects collectively influence the observed ICR behavior. These findings provide new insights into ion transport in IL/aqueous systems and offer valuable guidelines for designing nanopipette-based ion sensors and nanofluidic devices.
{"title":"Ionic Current Rectification Behaviors in Quartz Nanopipettes with Ionic Liquids/Aqueous Solution Systems","authors":"Xiaodong He, Xingjin Xiao, Yongxiang Guan, Xinshuang Cui","doi":"10.1016/j.electacta.2025.146282","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146282","url":null,"abstract":"Understanding ion transport behaviors in confined ionic liquid (IL)/aqueous solution systems is crucial for advancing nanofluidic device applications. In this study, we investigate the ionic current behaviors of such systems using quartz nanopipettes, revealing significant ionic current rectification (ICR) phenomena at the nanoscale, which are absent at the microscale. Experimental results show that in the absence of an external bias voltage, diffusion currents in nanopipettes are negative due to the liquid-junction potential at the IL/aqueous interface. The rectification ratio (R) increases from 1.47 to 11.64 as the KCl electrolyte concentration increases from 0.01 M to 1 M, indicating a unique behavior distinct from conventional aqueous systems. Additionally, different ILs exhibit varying rectification strengths, following the sequence: [Bmim] [BF<sub>4</sub>]> [Bmim] [NTf<sub>2</sub>]> [Bmim] [PF<sub>6</sub>]> [Bmim] [N(CN)<sub>2</sub>]. To further elucidate the underlying mechanisms, we conducted finite element simulation using a Poisson-Nernst-Planck model. The simulation results further demonstrate that IL diffusion, electrostatic interactions, and electric double layer effects collectively influence the observed ICR behavior. These findings provide new insights into ion transport in IL/aqueous systems and offer valuable guidelines for designing nanopipette-based ion sensors and nanofluidic devices.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"2 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electrodeposited nickel, cobalt, and their alloys are critical for applications including energy storage, electrocatalysis and magnetic devices. Traditional aqueous electrodeposition suffers from hydrogen evolution, causing embrittlement, while deep eutectic solvents (DES) offer a promising alternative owing to their low water activity. Here, amino acid-metal nitrate DES (Ni(NO3)2 and/or Co(NO3)2-L-serine) are introduced, and the electrochemical nucleation and growth mechanisms of Ni, Co, and their alloys are investigated. Cyclic voltammetry and potentiostatic transient analyses reveal potential-dependent nucleation and growth behavior. Electrodeposition of Ni from Ni(NO3)2/L-serine DES exhibits a two-stage nucleation and growth behavior. The electrodeposition of Co from Co(NO3)2/L-serine DES follows a three-dimensional progressive nucleation mechanism. A new model integrating proton reduction and adsorption with Scharifker-Mostany model for monometallic deposition and with Scharifker model for alloy deposition is proposed to interpret potentiostatic current transient behavior. The deposits are characterized by X-ray diffraction and scanning electron microscopy and the metal phases are confirmed.
{"title":"Electrochemical metal nucleation and growth mechanism from metal nitrate-L-serine deep eutectic solvent","authors":"Shuling Liu, Yanling Hu, Xinyi Lu, Bowen Xin, Zeyi Wang, Yihao Li, Zhikai Hu, Chao Wang","doi":"10.1016/j.electacta.2025.146279","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146279","url":null,"abstract":"Electrodeposited nickel, cobalt, and their alloys are critical for applications including energy storage, electrocatalysis and magnetic devices. Traditional aqueous electrodeposition suffers from hydrogen evolution, causing embrittlement, while deep eutectic solvents (DES) offer a promising alternative owing to their low water activity. Here, amino acid-metal nitrate DES (Ni(NO<sub>3</sub>)<sub>2</sub> and/or Co(NO<sub>3</sub>)<sub>2</sub>-L-serine) are introduced, and the electrochemical nucleation and growth mechanisms of Ni, Co, and their alloys are investigated. Cyclic voltammetry and potentiostatic transient analyses reveal potential-dependent nucleation and growth behavior. Electrodeposition of Ni from Ni(NO<sub>3</sub>)<sub>2</sub>/L-serine DES exhibits a two-stage nucleation and growth behavior. The electrodeposition of Co from Co(NO<sub>3</sub>)<sub>2</sub>/L-serine DES follows a three-dimensional progressive nucleation mechanism. A new model integrating proton reduction and adsorption with Scharifker-Mostany model for monometallic deposition and with Scharifker model for alloy deposition is proposed to interpret potentiostatic current transient behavior. The deposits are characterized by X-ray diffraction and scanning electron microscopy and the metal phases are confirmed.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"47 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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