Braga-Goodenough all-solid-state Na-Fc and Li-MnO2 batteries demonstrate deposition of Na and Li on the cathode during discharge. These reaction mechanisms were investigated in light of the generalized charge neutrality level and the experimental results of Braga et al., and two new types of mechanisms were proposed. The Na-Fc mechanism is represented by a multi-step C[(CE)cC]n mechanism where C is the chemical step, E is the electrochemical step, c is the catalytic (CE) step, and n denotes the number of [(CE)cC] part cycles. The nth cycle corresponds to n moles of Na and Li deposition. For Li-MnO2, two mechanisms were considered. One is the C[(CE)cC]n mechanism which is the same as Na-Fc, and the other is the C[2(CE)cC]n mechanism, which involves two consecutive (CE)c steps. In the C step of (CE)c of both mechanisms, Fc and MnO2 reduce Na+(sf) and Li+(sf) (sf - surface states) to deposit Na and Li, respectively, which are intramolecular charge transfer reactions within the adsorbed molecules. Fc and MnO2 are oxidized to intermediates immediately reduced to Fc and MnO2 by their anodes in the subsequent E step. Based on these mechanisms, these batteries' discharge capacity and cathode alkali metal deposition were examined in detail.
{"title":"Cathode reaction models for Braga-Goodenough Na-ferrocene and Li-MnO2 rechargeable batteries","authors":"M. Sakai","doi":"10.5599/jese.1704","DOIUrl":"https://doi.org/10.5599/jese.1704","url":null,"abstract":"Braga-Goodenough all-solid-state Na-Fc and Li-MnO2 batteries demonstrate deposition of Na and Li on the cathode during discharge. These reaction mechanisms were investigated in light of the generalized charge neutrality level and the experimental results of Braga et al., and two new types of mechanisms were proposed. The Na-Fc mechanism is represented by a multi-step C[(CE)cC]n mechanism where C is the chemical step, E is the electrochemical step, c is the catalytic (CE) step, and n denotes the number of [(CE)cC] part cycles. The nth cycle corresponds to n moles of Na and Li deposition. For Li-MnO2, two mechanisms were considered. One is the C[(CE)cC]n mechanism which is the same as Na-Fc, and the other is the C[2(CE)cC]n mechanism, which involves two consecutive (CE)c steps. In the C step of (CE)c of both mechanisms, Fc and MnO2 reduce Na+(sf) and Li+(sf) (sf - surface states) to deposit Na and Li, respectively, which are intramolecular charge transfer reactions within the adsorbed molecules. Fc and MnO2 are oxidized to intermediates immediately reduced to Fc and MnO2 by their anodes in the subsequent E step. Based on these mechanisms, these batteries' discharge capacity and cathode alkali metal deposition were examined in detail.","PeriodicalId":15660,"journal":{"name":"Journal of Electrochemical Science and Engineering","volume":"24 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76260715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chen Cai, Patrick McCormack, Ziyang Nie, Gary M. Koenig
Lithium-ion batteries are increasingly important for providing energy storage solutions. In the drive to improve the energy density at the cell level, optimizing the electrode architecture is crucial in addition to researching new materials. Binder-free (BF) electrodes include porous pellets only containing battery electroactive materials. These electrodes can provide advantages with regard to mechanical stability and alleviated ion transport limitations relative to composite approaches for very thick and energy-dense electrodes. However, the absence of conductive additives often limits suitable material candidates for BF battery electrodes. TiNb2O7 (TNO) is a promising BF electrode material from a gravimetric and volumetric capacity standpoint, but phase pure TNO has relatively low electronic conductivity. Herein, a sucrose precursor coating method for TNO materials was implemented to process the TNO materials into BF electrodes. The sucrose served as a source to generate carbon in the electrodes, where the carbon coating resulted in an increase in rate capability, discharge voltage, and cycle life.
{"title":"Impact of carbon coating processing using sucrose for thick binder-free titanium niobium oxide lithium-ion battery anode","authors":"Chen Cai, Patrick McCormack, Ziyang Nie, Gary M. Koenig","doi":"10.5599/jese.1655","DOIUrl":"https://doi.org/10.5599/jese.1655","url":null,"abstract":"Lithium-ion batteries are increasingly important for providing energy storage solutions. In the drive to improve the energy density at the cell level, optimizing the electrode architecture is crucial in addition to researching new materials. Binder-free (BF) electrodes include porous pellets only containing battery electroactive materials. These electrodes can provide advantages with regard to mechanical stability and alleviated ion transport limitations relative to composite approaches for very thick and energy-dense electrodes. However, the absence of conductive additives often limits suitable material candidates for BF battery electrodes. TiNb2O7 (TNO) is a promising BF electrode material from a gravimetric and volumetric capacity standpoint, but phase pure TNO has relatively low electronic conductivity. Herein, a sucrose precursor coating method for TNO materials was implemented to process the TNO materials into BF electrodes. The sucrose served as a source to generate carbon in the electrodes, where the carbon coating resulted in an increase in rate capability, discharge voltage, and cycle life.","PeriodicalId":15660,"journal":{"name":"Journal of Electrochemical Science and Engineering","volume":"1 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78794126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. H. Elagib, N. A. Kabbashi, M. Alam, M. Al-Khatib, M. Mirghani, E. Hassan
Due to the increasing demand for electrochemical energy storage, various novel electrode and catalysis materials for supercapacitors and rechargeable batteries have developed over the last decade. The structure and characteristics of these catalyst materials have a major effect on the device's performance. In order to lower the costs associated with electrochemical systems, electrochemical systems, metal-free catalysis materials can be employed. In this study, metal-free catalysts composed of nitrogen (N) and sulfur (S) dual-doped multi-walled carbon nanotubes were synthesized using a straightforward and cost-effective single-step hydrothermal method. Carbon nanotubes served as the carbon source, while l-cysteine amino acid and thiourea acted as doping elements. As a result of the physicochemical characterization, many defects and a porous structure were noted, along with the successful insertion of nitrogen and sulfur into the carbon nanotube was confirmed. According to the cyclic voltammetry tests for the dual-doped samples in alkaline conditions, the D-CNT2 catalyst exhibited onset potentials of -0.30 V higher than the -0.37 V observed for the D-CNT3 catalyst. This indicates enhanced oxygen–reduction reaction due to the synergistic effects of the heteroatoms in the structure and the presence of chemically active sites. Moreover, the outstanding specific capacitance of the D-CNT2 catalyst (214.12 F g-1 at scanning rates of 1 mV s-1) reflects the effective porosity of the proposed catalyst. These findings highlight the potential of N/S dual–doped carbon nanotubes for electrocatalytic applications, contributing to efficient energy conversion.
近十年来，由于对电化学储能的需求不断增加，各种用于超级电容器和可充电电池的新型电极和催化材料得到了发展。这些催化剂材料的结构和特性对装置的性能有很大的影响。为了降低与电化学系统相关的成本，可以采用无金属的电化学系统催化材料。在本研究中，采用简单、经济的单步水热法合成了由氮(N)和硫(S)双掺杂多壁碳纳米管组成的无金属催化剂。碳纳米管作为碳源，l-半胱氨酸和硫脲作为掺杂元素。通过物理化学表征，发现了许多缺陷和多孔结构，并证实了氮和硫成功插入碳纳米管。根据双掺杂样品在碱性条件下的循环伏安测试，D-CNT2催化剂的起始电位比D-CNT3催化剂的-0.37 V高-0.30 V。这表明由于结构中杂原子的协同作用和化学活性位点的存在，氧还原反应增强。此外，D-CNT2催化剂出色的比电容(在扫描速率为1 mV s-1时为214.12 F -1)反映了所提出的催化剂的有效孔隙率。这些发现突出了N/S双掺杂碳纳米管在电催化应用中的潜力，有助于高效的能量转换。
{"title":"The performance of heteroatom-doped carbon nanotubes synthesized via a hydrothermal method on the oxygen reduction reaction and specific capacitance","authors":"T. H. Elagib, N. A. Kabbashi, M. Alam, M. Al-Khatib, M. Mirghani, E. Hassan","doi":"10.5599/jese.1697","DOIUrl":"https://doi.org/10.5599/jese.1697","url":null,"abstract":"Due to the increasing demand for electrochemical energy storage, various novel electrode and catalysis materials for supercapacitors and rechargeable batteries have developed over the last decade. The structure and characteristics of these catalyst materials have a major effect on the device's performance. In order to lower the costs associated with electrochemical systems, electrochemical systems, metal-free catalysis materials can be employed. In this study, metal-free catalysts composed of nitrogen (N) and sulfur (S) dual-doped multi-walled carbon nanotubes were synthesized using a straightforward and cost-effective single-step hydrothermal method. Carbon nanotubes served as the carbon source, while l-cysteine amino acid and thiourea acted as doping elements. As a result of the physicochemical characterization, many defects and a porous structure were noted, along with the successful insertion of nitrogen and sulfur into the carbon nanotube was confirmed. According to the cyclic voltammetry tests for the dual-doped samples in alkaline conditions, the D-CNT2 catalyst exhibited onset potentials of -0.30 V higher than the -0.37 V observed for the D-CNT3 catalyst. This indicates enhanced oxygen–reduction reaction due to the synergistic effects of the heteroatoms in the structure and the presence of chemically active sites. Moreover, the outstanding specific capacitance of the D-CNT2 catalyst (214.12 F g-1 at scanning rates of 1 mV s-1) reflects the effective porosity of the proposed catalyst. These findings highlight the potential of N/S dual–doped carbon nanotubes for electrocatalytic applications, contributing to efficient energy conversion.","PeriodicalId":15660,"journal":{"name":"Journal of Electrochemical Science and Engineering","volume":"61 5 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73543808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Non-covalent modification of electrode surfaces with nanoparticle-based peptides does not change the chemical properties of the electrode but allows electrochemical measurement of cell adhesion. This study examines the effect of self-modified nanomaterial/peptide surfaces on cell adhesion. This adhesion to the surface is caused by the negative Gibs free energy formed in the system because of the presence of -0H, sulfur, carbonyl, or reactive groups. A cheaper and more practical method for electrode surfaces targeting cell adhesion, which does not use heavy chemicals and EDC/NHS chemistry, is used in this work. Thanks to the bioactive materials immobilized on the screen-printed carbon electrode (SPCE) surface in a controlled manner and the surface chemistry offered by these materials, a biocompatible self-assembling nanomaterial-based peptide surface platform is created, and cell adhesion is measured by an electrochemical technique. After the characterization steps, electrochemical techniques created a calibration curve of the current value as a function of concentration for each cell line. The adhesion of the generated bioactive electrode surfaces to the selected cell lines was examined comparatively.
{"title":"Self-assembling nanomaterial-based peptide surface for target cell adhesion","authors":"Hasret Turkmen","doi":"10.5599/jese.1664","DOIUrl":"https://doi.org/10.5599/jese.1664","url":null,"abstract":"Non-covalent modification of electrode surfaces with nanoparticle-based peptides does not change the chemical properties of the electrode but allows electrochemical measurement of cell adhesion. This study examines the effect of self-modified nanomaterial/peptide surfaces on cell adhesion. This adhesion to the surface is caused by the negative Gibs free energy formed in the system because of the presence of -0H, sulfur, carbonyl, or reactive groups. A cheaper and more practical method for electrode surfaces targeting cell adhesion, which does not use heavy chemicals and EDC/NHS chemistry, is used in this work. Thanks to the bioactive materials immobilized on the screen-printed carbon electrode (SPCE) surface in a controlled manner and the surface chemistry offered by these materials, a biocompatible self-assembling nanomaterial-based peptide surface platform is created, and cell adhesion is measured by an electrochemical technique. After the characterization steps, electrochemical techniques created a calibration curve of the current value as a function of concentration for each cell line. The adhesion of the generated bioactive electrode surfaces to the selected cell lines was examined comparatively.","PeriodicalId":15660,"journal":{"name":"Journal of Electrochemical Science and Engineering","volume":"41 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90322238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ivana Zrinski, Dominik Knapic, A. W. Hassel, A. I. Mardare
The development of miniaturized and portable sensing devices is crucial to meeting the high processing capacity demands of contemporary computing systems. Hence, the conceptualization of memristive sensors for hydroxide-containing liquids is proposed in this study. Metal-insulator-metal (MIM) structures were formed on electrochemically anodized Hf thin films with Pt patterned as top electrodes. These MIM memristive structures were integrated into a crossbar array, allowing the investigation of a high number of potential memristor sensors. The MIM structures have demonstrated sensing possibilities in the detection of the hydroxyl ion in D-glucose, used as a standard solution. The sensing method was based on the resistive state ratio extracted from I-U sweeps measurements. Analytical characterization of the memristor sensor was done based on the resistive state ratio in relation to different concentrations of a standard solution drop cast directly on the surface of the device. Linearity was found for D-glucose concentrations ranging from 10 mM to 80 mM with a reasonable corresponding correlation factor (R2=0.96809). Additionally, D-glucose incorporation in anodic oxide was studied by XPS to investigate its effect on conductive filaments formation. A carbon bonded by a single covalent bond to oxygen (O-C-O) was detected, confirming the proposed sensing mechanism defined by the glucose penetrating the oxide/electrode interface.
{"title":"Anodic HfO2 crossbar arrays for hydroxide-based memristive sensing in liquids","authors":"Ivana Zrinski, Dominik Knapic, A. W. Hassel, A. I. Mardare","doi":"10.5599/jese.1644","DOIUrl":"https://doi.org/10.5599/jese.1644","url":null,"abstract":"The development of miniaturized and portable sensing devices is crucial to meeting the high processing capacity demands of contemporary computing systems. Hence, the conceptualization of memristive sensors for hydroxide-containing liquids is proposed in this study. Metal-insulator-metal (MIM) structures were formed on electrochemically anodized Hf thin films with Pt patterned as top electrodes. These MIM memristive structures were integrated into a crossbar array, allowing the investigation of a high number of potential memristor sensors. The MIM structures have demonstrated sensing possibilities in the detection of the hydroxyl ion in D-glucose, used as a standard solution. The sensing method was based on the resistive state ratio extracted from I-U sweeps measurements. Analytical characterization of the memristor sensor was done based on the resistive state ratio in relation to different concentrations of a standard solution drop cast directly on the surface of the device. Linearity was found for D-glucose concentrations ranging from 10 mM to 80 mM with a reasonable corresponding correlation factor (R2=0.96809). Additionally, D-glucose incorporation in anodic oxide was studied by XPS to investigate its effect on conductive filaments formation. A carbon bonded by a single covalent bond to oxygen (O-C-O) was detected, confirming the proposed sensing mechanism defined by the glucose penetrating the oxide/electrode interface.","PeriodicalId":15660,"journal":{"name":"Journal of Electrochemical Science and Engineering","volume":"4 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87445108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michaela Roschger, Sigrid Wolf, Andreas Billiani, S. Gorgieva, Boštjan Genorio, V. Hacker
The direct electrochemical conversion of ethanol, a sustainable fuel, is an alternative sustainable technology of the future. In this study, membrane electrode assemblies with different electrode configurations for an alkaline direct ethanol fuel cell were fabricated and tested in a fuel cell device. The configurations include a catalyst-coated substrate (CCS), a catalyst-coated membrane (CCM), and a mixture of these two fabrication options. Two different anion exchange membranes were used to perform a comprehensive analysis. The fabricated CCSs and CCMs were characterized with single cell measurements, electrochemical impedance spectroscopy and scanning electron microscopy. In addition, the swelling behavior of the membranes in alkaline solution was investigated in order to obtain information for CCM production. The results of the experimental electrochemical tests show that the CCS approach provides higher power densities (42.4 mW cm-2) than the others, regardless of the membrane type.
{"title":"Electrode configurations study for alkaline direct ethanol fuel cells","authors":"Michaela Roschger, Sigrid Wolf, Andreas Billiani, S. Gorgieva, Boštjan Genorio, V. Hacker","doi":"10.5599/jese.1623","DOIUrl":"https://doi.org/10.5599/jese.1623","url":null,"abstract":"The direct electrochemical conversion of ethanol, a sustainable fuel, is an alternative sustainable technology of the future. In this study, membrane electrode assemblies with different electrode configurations for an alkaline direct ethanol fuel cell were fabricated and tested in a fuel cell device. The configurations include a catalyst-coated substrate (CCS), a catalyst-coated membrane (CCM), and a mixture of these two fabrication options. Two different anion exchange membranes were used to perform a comprehensive analysis. The fabricated CCSs and CCMs were characterized with single cell measurements, electrochemical impedance spectroscopy and scanning electron microscopy. In addition, the swelling behavior of the membranes in alkaline solution was investigated in order to obtain information for CCM production. The results of the experimental electrochemical tests show that the CCS approach provides higher power densities (42.4 mW cm-2) than the others, regardless of the membrane type.","PeriodicalId":15660,"journal":{"name":"Journal of Electrochemical Science and Engineering","volume":"1 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90269633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F.S. Volkov, S. Eliseeva, M. A. Kamenskii, A. Volkov, E. G. Tolstopjatova, V. Kondratiev
Vanadium oxide composites with conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) were obtained by one-step microwave-assisted hydrothermal synthesis at two different temperatures: 120 and 170 °C (denoted as V-120 and V-170, respectively). The structure and composition of the obtained samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and thermogravimetric (TG) analysis. The detailed study of the electrochemical properties of the composites as cathodes of aqueous zinc-ion battery was performed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) at different current densities and by electrochemical impedance spectroscopy (EIS). It was shown that V-120 demonstrated excellent electrochemical performance in the 0.3 to 1.4 V vs. Zn/Zn2+ potential range reaching specific capacities of up to 390 mA∙h∙g−1 at 0.3 A∙g−1 with excellent capacity stability after 1000 charge-discharge cycles. Its functional parameters were found to be much better than those of the electrodes based on the V-170 composite obtained at a higher temperature. The effect of the synthesis temperature on the electrochemical properties is discussed in terms of the crystallographic, compositional, and thermogravimetric properties of the samples.
采用微波辅助水热合成法，在120℃和170℃(分别记为V-120和V-170)条件下，一步合成了导电聚合物聚(3,4-乙烯二氧噻吩)氧化钒复合材料。通过扫描电镜(SEM)、x射线衍射(XRD)、x射线光电子能谱(XPS)和热重(TG)分析对所得样品的结构和组成进行了表征。采用循环伏安法(CV)、不同电流密度下恒流充放电法(GCD)和电化学阻抗谱法(EIS)对复合材料作为锌离子电池阴极的电化学性能进行了详细的研究。结果表明，V-120在0.3 ~ 1.4 V vs. Zn/Zn2+电位范围内表现出优异的电化学性能，在0.3 A∙g−1电压下比容量高达390 mA∙h∙g−1，且在1000次充放电循环后具有优异的容量稳定性。其功能参数明显优于高温下制备的V-170复合材料电极。从晶体学、成分学和热重学等方面讨论了合成温度对样品电化学性能的影响。
{"title":"Vanadium oxide - poly(3,4-ethylenedioxythiophene) cathodes for zinc-ion batteries: effect of synthesis temperature","authors":"F.S. Volkov, S. Eliseeva, M. A. Kamenskii, A. Volkov, E. G. Tolstopjatova, V. Kondratiev","doi":"10.5599/jese.1595","DOIUrl":"https://doi.org/10.5599/jese.1595","url":null,"abstract":"Vanadium oxide composites with conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) were obtained by one-step microwave-assisted hydrothermal synthesis at two different temperatures: 120 and 170 °C (denoted as V-120 and V-170, respectively). The structure and composition of the obtained samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and thermogravimetric (TG) analysis. The detailed study of the electrochemical properties of the composites as cathodes of aqueous zinc-ion battery was performed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) at different current densities and by electrochemical impedance spectroscopy (EIS). It was shown that V-120 demonstrated excellent electrochemical performance in the 0.3 to 1.4 V vs. Zn/Zn2+ potential range reaching specific capacities of up to 390 mA∙h∙g−1 at 0.3 A∙g−1 with excellent capacity stability after 1000 charge-discharge cycles. Its functional parameters were found to be much better than those of the electrodes based on the V-170 composite obtained at a higher temperature. The effect of the synthesis temperature on the electrochemical properties is discussed in terms of the crystallographic, compositional, and thermogravimetric properties of the samples.","PeriodicalId":15660,"journal":{"name":"Journal of Electrochemical Science and Engineering","volume":"253 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89467112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Basori, W. Mohamad, M. R. Mansor, N. Tamaldin, Agung Iswandi, M. K. Ajiriyanto, F. B. Susetyo
Hydrogen production could be enhanced by increasing the potassium hydroxide (KOH) concentration, but higher KOH concentrations result in higher corrosion rates. Therefore, a deep investigation of the electrochemical behavior of stainless steel (SS 316L) in the KOH solution is needed. This study investigates the influence of KOH concentrations on the electrochemical behavior, surface morphology, structure, and sample phases of SS 316L. The investigations were conducted by some electrochemical techniques, UV-vis, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and X-ray diffraction (XRD). The corrosion rate was found to increase, and solution resistance to decrease with increasing KOH concentration. Samples tested in 5, 30, and 50 g l-1 of KOH showed corrosion rates of 0.457, 2.362, and 5.613 µm year-1, respectively. A wide passive region and the noblest pitting potential were noticed for the sample with 5 g l-1 of KOH. Moreover, Mott-Schottky plots and characteristic wavelengths of UV-Vis suggest the formation of iron and chromium oxides by the passivation of samples. The SEM analysis showed a dynamic change of surface morphology from the lowest to the highest concentration with the intergranular corrosion found at the grain boundaries area. In conclusion, concentrations < 50 g l-1 KOH could be recommended since they would support the optimum remaining life of SS 316 L plates in HHO generators.
提高氢氧化钾(KOH)浓度可以促进产氢，但KOH浓度越高，腐蚀速率越快。因此，有必要对不锈钢(SS 316L)在KOH溶液中的电化学行为进行深入研究。本文研究了KOH浓度对SS 316L的电化学行为、表面形貌、结构和样品相的影响。采用电化学、紫外-可见、扫描电镜-能谱(SEM-EDS)、x射线衍射(XRD)等技术对其进行了研究。随着KOH浓度的增加，腐蚀速率增加，耐溶性降低。在5、30和50 g l-1 KOH中测试的样品显示，腐蚀速率分别为0.457、2.362和5.613µm。当KOH浓度为5 g l-1时，钝化区宽，点蚀电位高。此外，Mott-Schottky图和UV-Vis特征波长表明样品钝化形成了铁和铬的氧化物。扫描电镜分析表明，在晶界区域出现晶间腐蚀，表面形貌从最低浓度到最高浓度呈动态变化。总之，可以推荐浓度< 50 g L -1 KOH，因为它们可以支持HHO发生器中SS 316l板的最佳剩余寿命。
{"title":"Effect of KOH concentration on corrosion behavior and surface morphology of stainless steel 316L for HHO generator application","authors":"B. Basori, W. Mohamad, M. R. Mansor, N. Tamaldin, Agung Iswandi, M. K. Ajiriyanto, F. B. Susetyo","doi":"10.5599/jese.1615","DOIUrl":"https://doi.org/10.5599/jese.1615","url":null,"abstract":"Hydrogen production could be enhanced by increasing the potassium hydroxide (KOH) concentration, but higher KOH concentrations result in higher corrosion rates. Therefore, a deep investigation of the electrochemical behavior of stainless steel (SS 316L) in the KOH solution is needed. This study investigates the influence of KOH concentrations on the electrochemical behavior, surface morphology, structure, and sample phases of SS 316L. The investigations were conducted by some electrochemical techniques, UV-vis, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and X-ray diffraction (XRD). The corrosion rate was found to increase, and solution resistance to decrease with increasing KOH concentration. Samples tested in 5, 30, and 50 g l-1 of KOH showed corrosion rates of 0.457, 2.362, and 5.613 µm year-1, respectively. A wide passive region and the noblest pitting potential were noticed for the sample with 5 g l-1 of KOH. Moreover, Mott-Schottky plots and characteristic wavelengths of UV-Vis suggest the formation of iron and chromium oxides by the passivation of samples. The SEM analysis showed a dynamic change of surface morphology from the lowest to the highest concentration with the intergranular corrosion found at the grain boundaries area. In conclusion, concentrations < 50 g l-1 KOH could be recommended since they would support the optimum remaining life of SS 316 L plates in HHO generators.","PeriodicalId":15660,"journal":{"name":"Journal of Electrochemical Science and Engineering","volume":"9 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81693837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Simulations are performed to study the effect of performance parameters on the velocity profiles in a vanadium redox flow battery. The effect of flow rate, viscosity, porosity, electrode thickness, and effect of channel height on the velocity profile in a vanadium redox flow battery are studied. Quantitative analysis of velocity profiles at the mid height of channel, at the channel-electrode interface and mid height of electrode thickness is done. The channel height, thickness and porosity are found to have a substantial effect on the velocity profiles across the battery. It was found that the velocity in the electrode-channel interface is about 3 orders of magnitude lower than velocity in the channels.
{"title":"Modeling the velocity profiles in Vanadium Redox flow batteries-Serpentine flow field","authors":"Sarede Yadav, B. Krishnamurthy","doi":"10.5599/jese.1610","DOIUrl":"https://doi.org/10.5599/jese.1610","url":null,"abstract":" Simulations are performed to study the effect of performance parameters on the velocity profiles in a vanadium redox flow battery. The effect of flow rate, viscosity, porosity, electrode thickness, and effect of channel height on the velocity profile in a vanadium redox flow battery are studied. Quantitative analysis of velocity profiles at the mid height of channel, at the channel-electrode interface and mid height of electrode thickness is done. The channel height, thickness and porosity are found to have a substantial effect on the velocity profiles across the battery. It was found that the velocity in the electrode-channel interface is about 3 orders of magnitude lower than velocity in the channels.","PeriodicalId":15660,"journal":{"name":"Journal of Electrochemical Science and Engineering","volume":"14 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88741913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ethyl acetate extract of Asphodelus ramosus (ARAE) was examined as an anti-corrosion agent for carbon steel (CS) in 1 M HCl acid medium using different techniques, namely weight loss method, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) at various temperatures and inhibitor concentrations. An inhibition efficiency of 89.81 % was obtained by the weight loss method at the inhibitor concentration of 700 ppm at 293 K. Increasing the temperature decreases the corrosion inhibition rate. Potentiodynamic polarization results showed that the extract is adsorbed on CS surface according to the Freundlich isotherm, while negative values of the standard free energy of adsorption (DG0ads) suggested the physical spontaneity of the adsorption reaction. Scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) analyses were performed to examine the surface morphology of inhibited and uninhibited CS samples. Central composite design (CCD) based optimization was engaged to analyze factors and maximize inhibition efficiency by applying response surface methodology (RSM) using Design-Expert software.
采用失重法、动电位极化法和电化学阻抗光谱(EIS)等方法，在不同温度和抑制剂浓度条件下，对1 M HCl酸性介质中长叶石笋(Asphodelus ramosus, ARAE)乙酸乙酯提取物作为碳钢(CS)的防腐蚀剂进行了研究。在293k下，抑制剂浓度为700 ppm时，失重法的缓蚀率为89.81%。温度升高会降低缓蚀速率。电位动力学极化结果表明，根据Freundlich等温线，萃取物在CS表面被吸附，而标准吸附自由能(DG0ads)为负值表明吸附反应的物理自发性。采用扫描电镜(SEM)和能谱(EDS)分析了抑制和未抑制CS样品的表面形貌。利用design - expert软件，应用响应面法(RSM)，进行基于中心复合设计(CCD)的优化，分析影响因素，实现抑制效率最大化。
{"title":"Optimization of the inhibition corrosion of carbon steel in an acidic medium by a novel eco-friendly inhibitor Asphodelus ramosus using response surface methodology","authors":"Narimane Saigaa, Sabrina Bouguessa, Wafia Boukhedena, Mohammed Nacer, Ayoub Nadji, Abdelkarim Gouasmia","doi":"10.5599/jese.1628","DOIUrl":"https://doi.org/10.5599/jese.1628","url":null,"abstract":"Ethyl acetate extract of Asphodelus ramosus (ARAE) was examined as an anti-corrosion agent for carbon steel (CS) in 1 M HCl acid medium using different techniques, namely weight loss method, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) at various temperatures and inhibitor concentrations. An inhibition efficiency of 89.81 % was obtained by the weight loss method at the inhibitor concentration of 700 ppm at 293 K. Increasing the temperature decreases the corrosion inhibition rate. Potentiodynamic polarization results showed that the extract is adsorbed on CS surface according to the Freundlich isotherm, while negative values of the standard free energy of adsorption (DG0ads) suggested the physical spontaneity of the adsorption reaction. Scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) analyses were performed to examine the surface morphology of inhibited and uninhibited CS samples. Central composite design (CCD) based optimization was engaged to analyze factors and maximize inhibition efficiency by applying response surface methodology (RSM) using Design-Expert software.","PeriodicalId":15660,"journal":{"name":"Journal of Electrochemical Science and Engineering","volume":"14 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79018609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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