Pub Date : 2025-04-24DOI: 10.1016/j.electacta.2025.146306
A. Sharma, V.K. Beura, V.V. Joshi, K. Solanki
The enhancement of corrosion resistance in conventional magnesium alloys across a spectrum of environmental conditions, from alkaline to acidic regimes, remains a pivotal requirement for their widespread industrial adoption. This study investigates the impact of Friction Extrusion (FE) on microstructural refinement and its consequent influence on the corrosion behavior of cast Mg and Mg-3Si alloys. FE treatment effectively refined the magnesium microstructure by diminishing grain size and eliminating microstructural twins. Additionally, it homogenized the distribution and fragmented the cathodic Mg2Si particles in the Mg-3Si alloy. Both grain refinement and particle fragmentation markedly influenced the overall corrosion response, evident from the heightened cathodic kinetics observed in FE-processed samples. Time-resolved measurements of Mg2+ dissolution current, coupled with potentiodynamic polarization analyses, demonstrated an increased level of cathodically induced anodic dissolution in FE-processed Mg compared to the FE-treated Mg-3Si alloy. These experimental findings offer novel insights into the fundamental mechanisms governing corrosion resistance in magnesium alloys, underscoring the critical roles of solid-state processing techniques and initial alloy compositions in determining their corrosion behavior.
{"title":"Corrosion Behavior of Friction Extruded Magnesium Alloys: Grain Refinement and Particle Fragmentation Effect","authors":"A. Sharma, V.K. Beura, V.V. Joshi, K. Solanki","doi":"10.1016/j.electacta.2025.146306","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146306","url":null,"abstract":"The enhancement of corrosion resistance in conventional magnesium alloys across a spectrum of environmental conditions, from alkaline to acidic regimes, remains a pivotal requirement for their widespread industrial adoption. This study investigates the impact of Friction Extrusion (FE) on microstructural refinement and its consequent influence on the corrosion behavior of cast Mg and Mg-3Si alloys. FE treatment effectively refined the magnesium microstructure by diminishing grain size and eliminating microstructural twins. Additionally, it homogenized the distribution and fragmented the cathodic Mg<sub>2</sub>Si particles in the Mg-3Si alloy. Both grain refinement and particle fragmentation markedly influenced the overall corrosion response, evident from the heightened cathodic kinetics observed in FE-processed samples. Time-resolved measurements of Mg<sup>2+</sup> dissolution current, coupled with potentiodynamic polarization analyses, demonstrated an increased level of cathodically induced anodic dissolution in FE-processed Mg compared to the FE-treated Mg-3Si alloy. These experimental findings offer novel insights into the fundamental mechanisms governing corrosion resistance in magnesium alloys, underscoring the critical roles of solid-state processing techniques and initial alloy compositions in determining their corrosion behavior.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"7 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143867200","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 : 2025-04-24DOI: 10.1016/j.electacta.2025.146305
Hui Li, Hongfang Jiu, Lixin Zhang, Jinfeng Ma, Qian Xu, Yahui Wang, Xintong Chai, Kai Chen, Yunkai Zhang, Fan Wu
Lithium metal batteries (LMBs) hold significant promise for energy storage applications, yet they are hindered by low ionic conductivity and severe interfacial issues with the electrolyte. In this study, we developed a Co(NO3)2@CPEs system to address these challenges. By incorporating Co(NO3)2 additives and LLZTO nanoparticles into the PEO matrix, we aimed to reduce PEO crystallization and enhance Li+ transport. Additionally, this approach facilitated the formation of a Li3N-rich solid electrolyte interphase (SEI) layer. The study demonstrate that the inclusion of Co(NO3)2 promotes the generation of more Li3N, LiF, and Li2Co. These inorganic components significantly improve Li+ transport and help prevent the uneven deposition of lithium metal. Co(NO3)2@CPEs has an ionic conductivity of 4.96 × 10-4 S·cm-2 at 60°C (ionic conductivity of 2.4 × 10-5 S·cm-2 at 30°C), a Li+ migration number of 0.41, and an electrochemical window of 4.5 V. In addition, the lithium-symmetric battery can be stably cycled for 800 h at a current density of 0.2 mA·cm-2. The lithium metal battery with lithium iron phosphate (LiFePO4) as the cathode, on the other hand, has good multiplication capability and cycling stability, in which it can be cycled for 200 revolutions at 0.5 C and has an initial specific capacity of 148.08 mAh·g-1.
{"title":"Composite polymer electrolytes containing Co(NO3)2 can construct Li3N-rich interfacial layers in lithium-metal batteries","authors":"Hui Li, Hongfang Jiu, Lixin Zhang, Jinfeng Ma, Qian Xu, Yahui Wang, Xintong Chai, Kai Chen, Yunkai Zhang, Fan Wu","doi":"10.1016/j.electacta.2025.146305","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146305","url":null,"abstract":"Lithium metal batteries (LMBs) hold significant promise for energy storage applications, yet they are hindered by low ionic conductivity and severe interfacial issues with the electrolyte. In this study, we developed a Co(NO<sub>3</sub>)<sub>2</sub>@CPEs system to address these challenges. By incorporating Co(NO<sub>3</sub>)<sub>2</sub> additives and LLZTO nanoparticles into the PEO matrix, we aimed to reduce PEO crystallization and enhance Li<sup>+</sup> transport. Additionally, this approach facilitated the formation of a Li3N-rich solid electrolyte interphase (SEI) layer. The study demonstrate that the inclusion of Co(NO<sub>3</sub>)<sub>2</sub> promotes the generation of more Li<sub>3</sub>N, LiF, and Li<sub>2</sub>Co. These inorganic components significantly improve Li<sup>+</sup> transport and help prevent the uneven deposition of lithium metal. Co(NO<sub>3</sub>)<sub>2</sub>@CPEs has an ionic conductivity of 4.96 × 10<sup>-4</sup> S·cm<sup>-2</sup> at 60°C (ionic conductivity of 2.4 × 10<sup>-5</sup> S·cm<sup>-2</sup> at 30°C), a Li<sup>+</sup> migration number of 0.41, and an electrochemical window of 4.5 V. In addition, the lithium-symmetric battery can be stably cycled for 800 h at a current density of 0.2 mA·cm<sup>-2</sup>. The lithium metal battery with lithium iron phosphate (LiFePO<sub>4</sub>) as the cathode, on the other hand, has good multiplication capability and cycling stability, in which it can be cycled for 200 revolutions at 0.5 C and has an initial specific capacity of 148.08 mAh·g<sup>-1</sup>.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"23 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143867081","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 : 2025-04-24DOI: 10.1016/j.electacta.2025.146260
Yongfang Chen, David Aili, Wenjing Zhang, Kobra Azizi, Lars N. Cleemann, Qingfeng Li
Thin and robust polybenzimidazole membranes are reinforced using polybenzimidazole fiber mats. The fiber mats are prepared by electrospinning followed by thermal curing to enhance their dimensional and structural stability in phosphoric acid. These properties are evaluated through solubility tests in dimethylacetamide and swelling tests by phosphoric acid doping. The fiber reinforced membranes are in two distinct phases, a rigid crosslinked polybenzimidazole fiber mat within a continuous polybenzimidazole matrix. This was found to promote the anisotropic swelling during the subsequent phosphoric acid doping, i.e. suppressing the area swelling while enhancing the thickness swelling. Fuel cells equipped with thin composite membranes show high open circuit voltages and reasonable hydrogen crossover rate indicating dense composite membranes. The expected reduction in the ohmic resistance of fuel cells is not observed due to a reduced amount of acid in thinner membranes. Approaches to increasing the acid inventory in MEAs are under further evaluation.
{"title":"Reinforced Polybenzimidazole Membranes by Crosslinked Fiber Mats for High Temperature Polymer Electrolyte Membrane Fuel Cells","authors":"Yongfang Chen, David Aili, Wenjing Zhang, Kobra Azizi, Lars N. Cleemann, Qingfeng Li","doi":"10.1016/j.electacta.2025.146260","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146260","url":null,"abstract":"Thin and robust polybenzimidazole membranes are reinforced using polybenzimidazole fiber mats. The fiber mats are prepared by electrospinning followed by thermal curing to enhance their dimensional and structural stability in phosphoric acid. These properties are evaluated through solubility tests in dimethylacetamide and swelling tests by phosphoric acid doping. The fiber reinforced membranes are in two distinct phases, a rigid crosslinked polybenzimidazole fiber mat within a continuous polybenzimidazole matrix. This was found to promote the anisotropic swelling during the subsequent phosphoric acid doping, i.e. suppressing the area swelling while enhancing the thickness swelling. Fuel cells equipped with thin composite membranes show high open circuit voltages and reasonable hydrogen crossover rate indicating dense composite membranes. The expected reduction in the ohmic resistance of fuel cells is not observed due to a reduced amount of acid in thinner membranes. Approaches to increasing the acid inventory in MEAs are under further evaluation.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"25 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143867199","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}
O3-type NaNi1/3Fe1/3Mn1/3O2 is considered as one of the most promising cathode candidates for sodium-ion batteries due to its high specific density and low cost. However, rapid capacity degradation and sluggish diffusion kinetics, caused by structural distortions and irreversible phase transitions, present significant challenges to its commercial application. In this study, we design a series of O3-NaNi1/3-xFe1/3Mn1/3AlxO2 cathodes with varying Al3+ doping concentrations, synthesized through a one-step liquid-phase modified precursor method followed by post-calcination. Notably, an optimal level of Al3+ substitution at the transition metal sites significantly enhances the structural stability during long cycling. However, excessive Al doping at the Na-site hampers sodium-ions diffusion, thereby limiting the rate performance. The optimal performance is achieved with the O3-NaNi1/3-0.005Fe1/3Mn1/3Al0.005O2 cathode, which exhibits remarkable overall electrochemical performance including a high specific capacity of 151 mAh g-1 at 1 C, superior cycle stability with 85% capacity retention after 150 cycles in a half cell, and improved rate performance (74 mAh g-1 at 10 C). This work provides valuable insights into the behavior of inactive element substitution, offering a pathway for the development of long-cycle life O3-type oxide cathodes and contributing to novel materials design strategies.
{"title":"Unlocking long-lifespan O3-Type Oxide Cathode for Sodium-ion batteries via inactive element substitution","authors":"Liling Dai, Hao Li, Wanli Wei, Tonghui Xu, Wenwen Xue, Ya-Jun Cheng, Yonggao Xia","doi":"10.1016/j.electacta.2025.146308","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146308","url":null,"abstract":"O3-type NaNi<sub>1/3</sub>Fe<sub>1/3</sub>Mn<sub>1/3</sub>O<sub>2</sub> is considered as one of the most promising cathode candidates for sodium-ion batteries due to its high specific density and low cost. However, rapid capacity degradation and sluggish diffusion kinetics, caused by structural distortions and irreversible phase transitions, present significant challenges to its commercial application. In this study, we design a series of O3-NaNi<sub>1/3-x</sub>Fe<sub>1/3</sub>Mn<sub>1/3</sub>Al<sub>x</sub>O<sub>2</sub> cathodes with varying Al<sup>3+</sup> doping concentrations, synthesized through a one-step liquid-phase modified precursor method followed by post-calcination. Notably, an optimal level of Al<sup>3+</sup> substitution at the transition metal sites significantly enhances the structural stability during long cycling. However, excessive Al doping at the Na-site hampers sodium-ions diffusion, thereby limiting the rate performance. The optimal performance is achieved with the O3-NaNi<sub>1/3-0.005</sub>Fe<sub>1/3</sub>Mn<sub>1/3</sub>Al<sub>0.005</sub>O<sub>2</sub> cathode, which exhibits remarkable overall electrochemical performance including a high specific capacity of 151 mAh g<sup>-1</sup> at 1 C, superior cycle stability with 85% capacity retention after 150 cycles in a half cell, and improved rate performance (74 mAh g<sup>-1</sup> at 10 C). This work provides valuable insights into the behavior of inactive element substitution, offering a pathway for the development of long-cycle life O3-type oxide cathodes and contributing to novel materials design strategies.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"32 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143867201","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}
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}
Although there has been a lot of work towards the development of urea sensors, work towards the development of non-invasive or minimally invasive biosensors for personal healthcare remains scarce. Microneedle (MN)-based diagnostic presents a new avenue in personalized healthcare monitoring by utilizing interstitial fluid (ISF) as a biofluid and a viable alternative to conventional blood-based diagnostics. This work demonstrates the development of a wearable electrochemical sensor coupled with poly (ethylene glycol) diacrylate (PEDGA) based MN extraction platform to realize minimally invasive ISF-based real-time highly selective urea monitoring. The MNs with an average length of 782±10 µm are fabricated using stereolithography and the electrochemical enzymatic sensor is developed using a flexible carbon cloth (CC) electrode modified with NiSe2/MXene.The modified Urease/NiSe2/MXene/CC electrode exhibits a high sensitivity of 83.49 μAμM-1cm-2 (1μM to 20μM), 70 μAμM-1cm-2 (0.1mM to 1mM) and 20 μA mM-1 cm-2(0.1mM to 15mM), with high selectivity, with a response time of 398 seconds, and the lowest detection limit of 0.1214μM. Further, the validation of urea concentration in ISF with the developed sensor with the standard clinical method named Glutamate dehydrogenase (GLDH) suggests an error in the tolerable range. Finally, in-vivo studies of urea measurement were performed by inserting a 3D printed MN patch (10*10) in Sprague Dawley (SD) rat’s dorsal skin. The in-vivo studies revealed a urea concentration of ∼ 5.8 mM with a rapid response time of 398 seconds, which is exceptionally faster, and validated using the GLDH method. Successful demonstration for minimally invasive MN-based point-of-care diagnostic of biomarkers opens up new avenues of development for personal healthcare monitoring.
{"title":"Microneedle Array Integrated 2D NiSe2/MXene-based Real-Time Urea Sensing in Interstitial Fluid","authors":"Isha Basumatary, Shreya Shashank Chauhan, Venkata Vamsi Krishna Venuganti, Parikshit Sahatiya","doi":"10.1016/j.electacta.2025.146299","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146299","url":null,"abstract":"Although there has been a lot of work towards the development of urea sensors, work towards the development of non-invasive or minimally invasive biosensors for personal healthcare remains scarce. Microneedle (MN)-based diagnostic presents a new avenue in personalized healthcare monitoring by utilizing interstitial fluid (ISF) as a biofluid and a viable alternative to conventional blood-based diagnostics. This work demonstrates the development of a wearable electrochemical sensor coupled with poly (ethylene glycol) diacrylate (PEDGA) based MN extraction platform to realize minimally invasive ISF-based real-time highly selective urea monitoring. The MNs with an average length of 782±10 µm are fabricated using stereolithography and the electrochemical enzymatic sensor is developed using a flexible carbon cloth (CC) electrode modified with NiSe<sub>2</sub>/MXene.The modified Urease/NiSe<sub>2</sub>/MXene/CC electrode exhibits a high sensitivity of 83.49 μAμM<sup>-1</sup>cm<sup>-2</sup> (1μM to 20μM), 70 μAμM<sup>-1</sup>cm<sup>-2</sup> (0.1mM to 1mM) and 20 μA mM<sup>-1</sup> cm<sup>-2</sup>(0.1mM to 15mM), with high selectivity, with a response time of 398 seconds, and the lowest detection limit of 0.1214μM. Further, the validation of urea concentration in ISF with the developed sensor with the standard clinical method named Glutamate dehydrogenase (GLDH) suggests an error in the tolerable range. Finally, <em>in-vivo</em> studies of urea measurement were performed by inserting a 3D printed MN patch (10*10) in Sprague Dawley (SD) rat’s dorsal skin. The <em>in-vivo</em> studies revealed a urea concentration of ∼ 5.8 mM with a rapid response time of 398 seconds, which is exceptionally faster, and validated using the GLDH method. Successful demonstration for minimally invasive MN-based point-of-care diagnostic of biomarkers opens up new avenues of development for personal healthcare monitoring.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"31 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143867202","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.2025.146290
Haiyan Zhang, Yi Qian, Jing Pang, Jingdong Jiang, Xingge Liu, Qiyu Lan, Xiaopeng Qi, Jiantao Wang
Lithium iron phosphate batteries are considered one of the most popular power sources for electric vehicles and storage systems because of their excellent safety and cycle life. However, when degradation occurs, battery performance becomes unreliable. Thus, accurate identification of the battery performance during the long cycle is especially important. In this paper, the performance of LiFePO4/graphite cells cycled at different rates to 5000 cycles is compared in detail. During the cycle, the voltage, capacity, and reference performance tests are recorded to find the method for cell state assessment under operating conditions. We find that the voltages acquired from the end of the rest period can reflect the cell state of charge to some extent. The capacity differences between operating conditions and the capacity increase during the early cycle stage of rate discharge can all be explained clearly in terms of the changes in their corresponding rest voltages. Moreover, the voltage differences between the end of the rest period and the start of the operation are useful parameters to evaluate the change in ohmic polarization with the cycle. In addition, a non-destructive method is proposed by comparing the voltage and corresponding differential voltage curves of the cell and the two separate electrodes. Based on this method, the ageing states of cells cycled under different conditions are quantitatively evaluated. An increased capacity ratio of negative to positive during the cycle is discovered in cells with better cycle performance, providing theoretical support for cell design with ultra-long cycles.
{"title":"Insight into the effect of current rates on the ageing performance of LiFePO4/graphite cells with the ultra-long cycles","authors":"Haiyan Zhang, Yi Qian, Jing Pang, Jingdong Jiang, Xingge Liu, Qiyu Lan, Xiaopeng Qi, Jiantao Wang","doi":"10.1016/j.electacta.2025.146290","DOIUrl":"https://doi.org/10.1016/j.electacta.2025.146290","url":null,"abstract":"Lithium iron phosphate batteries are considered one of the most popular power sources for electric vehicles and storage systems because of their excellent safety and cycle life. However, when degradation occurs, battery performance becomes unreliable. Thus, accurate identification of the battery performance during the long cycle is especially important. In this paper, the performance of LiFePO<sub>4</sub>/graphite cells cycled at different rates to 5000 cycles is compared in detail. During the cycle, the voltage, capacity, and reference performance tests are recorded to find the method for cell state assessment under operating conditions. We find that the voltages acquired from the end of the rest period can reflect the cell state of charge to some extent. The capacity differences between operating conditions and the capacity increase during the early cycle stage of rate discharge can all be explained clearly in terms of the changes in their corresponding rest voltages. Moreover, the voltage differences between the end of the rest period and the start of the operation are useful parameters to evaluate the change in ohmic polarization with the cycle. In addition, a non-destructive method is proposed by comparing the voltage and corresponding differential voltage curves of the cell and the two separate electrodes. Based on this method, the ageing states of cells cycled under different conditions are quantitatively evaluated. An increased capacity ratio of negative to positive during the cycle is discovered in cells with better cycle performance, providing theoretical support for cell design with ultra-long cycles.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"42 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143867204","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}
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