Pub Date : 2024-12-30DOI: 10.1016/j.electacta.2024.145572
Mohammed Omer Farooq, Mohammad Furquan, Obaidallah Munteshari, Mohammad Qamar
This study analyzes the real-time temperature distribution patterns on the anode (negative electrode) and cathode (positive electrode) of the vanadium redox flow battery in a full-cell configuration. The patterns are analyzed under various current densities (60, 75, and 90 mA cm–2), electrolyte flow rates (50 and 100 mL min–1), and different operating temperatures of the cell and tanks (25 °C and 30 °C) during the galvanostatic cycling. The real-time temperature variations are recorded at the negative and positive electrodes during the charge-discharge cycling and then represented in 2D temperature distribution contours. It is noted that the temperature of the negative electrode increases during charging and falls during discharge. Conversely, the temperature of the positive electrode decreases during charging and increases during discharging. A comprehensive analysis and discussion of the temperature distribution at the electrodes are presented. Furthermore, the distribution of applied current density during the galvanostatic cycling at both electrodes is carefully mapped. The study offers valuable insights into the temperature distribution behavior of vanadium redox flow batteries, which could be advantageous for future technological advancements. Specifically, catholyte species precipitate during galvanostatic cycling at moderate temperatures, a problem for vanadium redox flow batteries.
{"title":"An operando investigation of temperature distribution behaviour in full-cell vanadium-redox flow batteries","authors":"Mohammed Omer Farooq, Mohammad Furquan, Obaidallah Munteshari, Mohammad Qamar","doi":"10.1016/j.electacta.2024.145572","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145572","url":null,"abstract":"This study analyzes the real-time temperature distribution patterns on the anode (negative electrode) and cathode (positive electrode) of the vanadium redox flow battery in a full-cell configuration. The patterns are analyzed under various current densities (60, 75, and 90 mA cm<sup>–2</sup>), electrolyte flow rates (50 and 100 mL min<sup>–1</sup>), and different operating temperatures of the cell and tanks (25 °C and 30 °C) during the galvanostatic cycling. The real-time temperature variations are recorded at the negative and positive electrodes during the charge-discharge cycling and then represented in 2D temperature distribution contours. It is noted that the temperature of the negative electrode increases during charging and falls during discharge. Conversely, the temperature of the positive electrode decreases during charging and increases during discharging. A comprehensive analysis and discussion of the temperature distribution at the electrodes are presented. Furthermore, the distribution of applied current density during the galvanostatic cycling at both electrodes is carefully mapped. The study offers valuable insights into the temperature distribution behavior of vanadium redox flow batteries, which could be advantageous for future technological advancements. Specifically, catholyte species precipitate during galvanostatic cycling at moderate temperatures, a problem for vanadium redox flow batteries.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"7 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901859","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 : 2024-12-30DOI: 10.1016/j.electacta.2024.145567
J.-B. Guy, W. Porcher, S. Chazelle, F. Bossard, E. Mayousse, B. Chavillon, S. Martinet
The electrode tortuosity is the ratio between the effective conductivity of the Li ion in the electrolyte phase of the electrode thickness and the electrolyte conductivity. This is a critical parameter for high rate application, particularly in battery charge for the negative electrode and notably for fast charge challenge in the electric vehicles’ (EV) application. A common method to measure it at macroscopic level is the electrochemical impedance spectroscopy in a symmetric cell configuration in blocking conditions. Such conditions can be obtained using a non-intercalating cation with generally a large steric hindrance. In this study, the electrolyte salt nature and concentration influence on the tortuosity measurement is investigated. Several electrolyte salts are evaluated with different cations or anions, including the conventional LiPF6 salt, considering different steric hindrance or affinity. A robust method is firstly developed by examining the effects of the temperature and the electrode porosity. Selecting an electrolyte concentration of 10 mM is an effective way to achieve tortuosity value with a precision lower than 0.15, approximately 3% of the tortuosity of a conventional graphite electrode. Finally, the electrolyte salt nature does not affect the electrode tortuosity measurement as long as an acceptable capacitive behavior is obtained.
{"title":"Influence of liquid electrolyte salt nature and concentration on tortuosity measurement of battery electrode","authors":"J.-B. Guy, W. Porcher, S. Chazelle, F. Bossard, E. Mayousse, B. Chavillon, S. Martinet","doi":"10.1016/j.electacta.2024.145567","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145567","url":null,"abstract":"The electrode tortuosity is the ratio between the effective conductivity of the Li ion in the electrolyte phase of the electrode thickness and the electrolyte conductivity. This is a critical parameter for high rate application, particularly in battery charge for the negative electrode and notably for fast charge challenge in the electric vehicles’ (EV) application. A common method to measure it at macroscopic level is the electrochemical impedance spectroscopy in a symmetric cell configuration in blocking conditions. Such conditions can be obtained using a non-intercalating cation with generally a large steric hindrance. In this study, the electrolyte salt nature and concentration influence on the tortuosity measurement is investigated. Several electrolyte salts are evaluated with different cations or anions, including the conventional LiPF<sub>6</sub> salt, considering different steric hindrance or affinity. A robust method is firstly developed by examining the effects of the temperature and the electrode porosity. Selecting an electrolyte concentration of 10 mM is an effective way to achieve tortuosity value with a precision lower than 0.15, approximately 3% of the tortuosity of a conventional graphite electrode. Finally, the electrolyte salt nature does not affect the electrode tortuosity measurement as long as an acceptable capacitive behavior is obtained.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"20 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901854","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 : 2024-12-30DOI: 10.1016/j.electacta.2024.145614
Said Al-Saidi, Htet Htet Kyaw, Myo Tay Zar Myint, Rashid Al-Hajri, Mohammed Al-Abri
Researchers have widely explored capacitive deionization (CDI) for brackish water desalination over the last decade, considering it a promising technology. Theoretical and statistical analyses are crucial for optimizing CDI performance parameters. This study utilizes response surface methodology (RSM) with central composite design (CCD) to systematically explore the impacts of crucial operational variables on CDI efficiency. Our analysis yielded a robust quadratic model with a high R-squared value (0.99), indicating excellent predictive capability. The CDI performance was conducted using activated carbon cloth electrodes and achieved a maximum removal efficiency of 40.6 % under optimal conditions of 1.8 V DC, 2 ml/min, and 500 mg/L NaCl. The increase in applied potential enhanced removal efficiency, whereas flow rate and NaCl concentration had adverse effects. The validity of the resulting model was further tested with various water sources such as groundwater and produced water, demonstrating its predictive capability when a pretreatment step is included. However, we recommend developing a new model for more robust optimization of CDI systems.
{"title":"Capacitive deionization for water desalination: Optimizing operational parameters and validating the model across concentrations variant","authors":"Said Al-Saidi, Htet Htet Kyaw, Myo Tay Zar Myint, Rashid Al-Hajri, Mohammed Al-Abri","doi":"10.1016/j.electacta.2024.145614","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145614","url":null,"abstract":"Researchers have widely explored capacitive deionization (CDI) for brackish water desalination over the last decade, considering it a promising technology. Theoretical and statistical analyses are crucial for optimizing CDI performance parameters. This study utilizes response surface methodology (RSM) with central composite design (CCD) to systematically explore the impacts of crucial operational variables on CDI efficiency. Our analysis yielded a robust quadratic model with a high R-squared value (0.99), indicating excellent predictive capability. The CDI performance was conducted using activated carbon cloth electrodes and achieved a maximum removal efficiency of 40.6 % under optimal conditions of 1.8 V DC, 2 ml/min, and 500 mg/L NaCl. The increase in applied potential enhanced removal efficiency, whereas flow rate and NaCl concentration had adverse effects. The validity of the resulting model was further tested with various water sources such as groundwater and produced water, demonstrating its predictive capability when a pretreatment step is included. However, we recommend developing a new model for more robust optimization of CDI systems.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"35 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901856","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 : 2024-12-30DOI: 10.1016/j.electacta.2024.145615
Dilek Vatansever
Bone broth (BB) and egg white (EW) gel electrolytes are prepared by containing NaCl and KCl salts. pH, conductivity and viscosity values are measured. Mass and energy changes with temperature are determined by thermogravimetric analysis and differential scanning calorimetry, respectively. Their molecular structures are investigated by Fourier transform infrared spectroscopy. Their suitability for supercapacitor devices is analyzed using pencil graphite (PGE)/polypyrrole (PPy) and PGE/PPy-Manganese oxide (MnOx) electrodes produced by electrodeposition. The interface between the electrode and the electrolyte is investigated by electrochemical impedance spectroscopy. The capacitive behavior of the electrodes is investigated by cyclic voltammetry and galvanostatic charge-discharge techniques. The highest specific capacitance value of the PGE/PPy-MnOx electrode is calculated as 450 F/g at a scan rate of 5 mV/s in a NaCl-BB gel electrolyte with a potential window between -0.1 and 1.0 V. The double layer and pseudo-capacitance contributions are calculated using Dunn's method. The pseudo-capacitance contribution is generally dominant. PGE/PPy-MnOx//NaCl-BB//PPy-MnOx/PGE and PGE/PPy-MnOx//KCl-EW//PPy-MnOx/PGE supercapacitor devices are fabricated and characterized. The calculated power densities are 320 and 600 W/kg and the cyclic stabilities are 52% and 88% after 200 cycles respectively. The values prove that these natural gels are quite suitable for energy storage applications.
{"title":"Supercapacitor applications of natural gel electrolytes prepared by bone broth and egg white","authors":"Dilek Vatansever","doi":"10.1016/j.electacta.2024.145615","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145615","url":null,"abstract":"Bone broth (BB) and egg white (EW) gel electrolytes are prepared by containing NaCl and KCl salts. pH, conductivity and viscosity values are measured. Mass and energy changes with temperature are determined by thermogravimetric analysis and differential scanning calorimetry, respectively. Their molecular structures are investigated by Fourier transform infrared spectroscopy. Their suitability for supercapacitor devices is analyzed using pencil graphite (PGE)/polypyrrole (PPy) and PGE/PPy-Manganese oxide (MnOx) electrodes produced by electrodeposition. The interface between the electrode and the electrolyte is investigated by electrochemical impedance spectroscopy. The capacitive behavior of the electrodes is investigated by cyclic voltammetry and galvanostatic charge-discharge techniques. The highest specific capacitance value of the PGE/PPy-MnOx electrode is calculated as 450 F/g at a scan rate of 5 mV/s in a NaCl-BB gel electrolyte with a potential window between -0.1 and 1.0 V. The double layer and pseudo-capacitance contributions are calculated using Dunn's method. The pseudo-capacitance contribution is generally dominant. PGE/PPy-MnOx//NaCl-BB//PPy-MnOx/PGE and PGE/PPy-MnOx//KCl-EW//PPy-MnOx/PGE supercapacitor devices are fabricated and characterized. The calculated power densities are 320 and 600 W/kg and the cyclic stabilities are 52% and 88% after 200 cycles respectively. The values prove that these natural gels are quite suitable for energy storage applications.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"83 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901855","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 : 2024-12-29DOI: 10.1016/j.electacta.2024.145604
Anchun Fang, Jiaheng Wang, Jie Zhou, Yang Zhao, Yulong Cao, Qingwei Wang, Linzhi Zhong, Jingyue He, Jiaxu Gong, Yatang Dai
The development of highly efficient and stable OER and HER bifunctional catalysts is important for sustainable energy conversion. Interfacial engineering is one of the most effective strategies to modulate the electronic structure of the active center to enhance the catalytic activity. Therefore, in this paper, NiMoO4 nanorods grown on nickel foam were annealed and etched to enable the formation of α-NiMoO4, β-NiMoO4 and NiS phases on the surface of the nanorods. This method enables controlled phase transformation and etching of the nanorod surface. As a bifunctional catalyst, NiS/NiMoO4 performs excellently, requiring only 270 mV and 270 mV overpotentials to reach 100 mA cm-2 for OER and HER, respectively. Excellent durability was demonstrated in a two-electrode electrolytic cell stability test at 100 mA cm-2 for 200 h. This study suggests a rational approach to interfacial design for improving catalyst activity.
{"title":"Interfacial engineering of NiS/NiMoO4 nanorod arrays to improve OER and HER performance for stable overall water splitting","authors":"Anchun Fang, Jiaheng Wang, Jie Zhou, Yang Zhao, Yulong Cao, Qingwei Wang, Linzhi Zhong, Jingyue He, Jiaxu Gong, Yatang Dai","doi":"10.1016/j.electacta.2024.145604","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145604","url":null,"abstract":"The development of highly efficient and stable OER and HER bifunctional catalysts is important for sustainable energy conversion. Interfacial engineering is one of the most effective strategies to modulate the electronic structure of the active center to enhance the catalytic activity. Therefore, in this paper, NiMoO<sub>4</sub> nanorods grown on nickel foam were annealed and etched to enable the formation of α-NiMoO<sub>4</sub>, β-NiMoO<sub>4</sub> and NiS phases on the surface of the nanorods. This method enables controlled phase transformation and etching of the nanorod surface. As a bifunctional catalyst, NiS/NiMoO<sub>4</sub> performs excellently, requiring only 270 mV and 270 mV overpotentials to reach 100 mA cm<sup>-2</sup> for OER and HER, respectively. Excellent durability was demonstrated in a two-electrode electrolytic cell stability test at 100 mA cm<sup>-2</sup> for 200 h. This study suggests a rational approach to interfacial design for improving catalyst activity.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"26 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901858","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}
In the field of energy storage, lithium-sulfur batteries are considered a highly promising energy storage technology due to their exceptional theoretical energy density. However, the "shuttle effect" of lithium polysulfides (LiPSs) and the sluggish redox kinetics of the sulfur cathode have hindered their commercialization. Addressing these challenges, this study successfully anchored Ni single atoms on N-Doped Hollow Carbon Spheres (Ni-NHCS) via a one-step impregnation method, fabricating an efficient sulfur carrier material. The Ni single atoms in Ni-NHCS form highly chemically active Ni-N coordination structures with nitrogen atoms, significantly enhancing the chemical adsorption capacity for LiPSs and effectively facilitating their conversion reactions. Experimental results and theoretical calculations both confirm the strong interaction between Ni-NHCS and LiPSs, thereby improving the utilization rate of sulfur and the electrochemical performance of the battery. Moreover, the hollow carbon sphere structure not only enhances the conductivity of sulfur but also effectively suppresses volume expansion during charge-discharge processes. Consequently, lithium-sulfur batteries with Ni-NHCS as the sulfur carrier material exhibit outstanding electrochemical performance, achieving a high specific capacity of 1316 mAh g-1 at a current density of 0.2 C; even at a high current density of 2 C, it can still provide a stable output of 697 mAh g-1. More impressively, after 2850 cycles under 2 C conditions, the capacity fade rate is only 0.027%, demonstrating excellent cyclic stability. By effectively suppressing the "shuttle effect" and optimizing redox kinetics, this study provides a new strategy for enhancing the performance of lithium-sulfur batteries. These findings not only validate the high-efficiency application potential of carbon-supported metal single-atom catalysts in sulfur cathode materials but also offer new insights for advancing lithium-sulfur battery technology and achieving sustainable, efficient energy storage solutions.
{"title":"Adsorption and Electrocatalytic properties of Polysulfides by Ni-N coordination structures","authors":"Wei Du, Yanshuang Meng, Jiangnan Zhang, Qiang Xiang, Jiawei Feng, Fuliang Zhu","doi":"10.1016/j.electacta.2024.145613","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145613","url":null,"abstract":"In the field of energy storage, lithium-sulfur batteries are considered a highly promising energy storage technology due to their exceptional theoretical energy density. However, the \"shuttle effect\" of lithium polysulfides (LiPSs) and the sluggish redox kinetics of the sulfur cathode have hindered their commercialization. Addressing these challenges, this study successfully anchored Ni single atoms on N-Doped Hollow Carbon Spheres (Ni-NHCS) via a one-step impregnation method, fabricating an efficient sulfur carrier material. The Ni single atoms in Ni-NHCS form highly chemically active Ni-N coordination structures with nitrogen atoms, significantly enhancing the chemical adsorption capacity for LiPSs and effectively facilitating their conversion reactions. Experimental results and theoretical calculations both confirm the strong interaction between Ni-NHCS and LiPSs, thereby improving the utilization rate of sulfur and the electrochemical performance of the battery. Moreover, the hollow carbon sphere structure not only enhances the conductivity of sulfur but also effectively suppresses volume expansion during charge-discharge processes. Consequently, lithium-sulfur batteries with Ni-NHCS as the sulfur carrier material exhibit outstanding electrochemical performance, achieving a high specific capacity of 1316 mAh g<sup>-1</sup> at a current density of 0.2 C; even at a high current density of 2 C, it can still provide a stable output of 697 mAh g<sup>-1</sup>. More impressively, after 2850 cycles under 2 C conditions, the capacity fade rate is only 0.027%, demonstrating excellent cyclic stability. By effectively suppressing the \"shuttle effect\" and optimizing redox kinetics, this study provides a new strategy for enhancing the performance of lithium-sulfur batteries. These findings not only validate the high-efficiency application potential of carbon-supported metal single-atom catalysts in sulfur cathode materials but also offer new insights for advancing lithium-sulfur battery technology and achieving sustainable, efficient energy storage solutions.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"5 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888838","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 : 2024-12-29DOI: 10.1016/j.electacta.2024.145600
Huichang Park, Ki Jun Kim, Seong Jung Kwon
As an application of single-entity electrochemistry (SEE), ultraviolet (UV) detection by SEE of single silver (Ag) nanoparticles (NPs) has been conducted. In this study, silver chloride (AgCl) NPs are converted to Ag NPs through UV irradiation, catalyzed by citrate. The oxidation current of the photoreduced Ag NPs are detected using SEE, exhibiting variations dependent on the UV wavelength and irradiation time. AgCl NPs exposed to light at wavelengths of 600 nm and 730 nm do not produce any current signal in the SEE measurement. However, at wavelengths of 254 and 365 nm, current signals are observed for SEE, with the signal frequency increasing with longer irradiation times. Frequency analysis of the signal reveals a significant difference between irradiation at 254 nm and 365 nm, indicating that the photoreduction rate of AgCl NPs irradiated at 254 nm is approximately 34 times faster than at 365 nm. These findings demonstrate the feasibility of applying SEE to study photoreaction characteristics and underscore the potential application of SEE in fabricating ultra-small UV sensors using minimal NP solution
{"title":"Application of Single-Entity Electrochemistry for Ultraviolet Detection Using Photoreduced Silver Nanoparticles","authors":"Huichang Park, Ki Jun Kim, Seong Jung Kwon","doi":"10.1016/j.electacta.2024.145600","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145600","url":null,"abstract":"As an application of single-entity electrochemistry (SEE), ultraviolet (UV) detection by SEE of single silver (Ag) nanoparticles (NPs) has been conducted. In this study, silver chloride (AgCl) NPs are converted to Ag NPs through UV irradiation, catalyzed by citrate. The oxidation current of the photoreduced Ag NPs are detected using SEE, exhibiting variations dependent on the UV wavelength and irradiation time. AgCl NPs exposed to light at wavelengths of 600 nm and 730 nm do not produce any current signal in the SEE measurement. However, at wavelengths of 254 and 365 nm, current signals are observed for SEE, with the signal frequency increasing with longer irradiation times. Frequency analysis of the signal reveals a significant difference between irradiation at 254 nm and 365 nm, indicating that the photoreduction rate of AgCl NPs irradiated at 254 nm is approximately 34 times faster than at 365 nm. These findings demonstrate the feasibility of applying SEE to study photoreaction characteristics and underscore the potential application of SEE in fabricating ultra-small UV sensors using minimal NP solution","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"26 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888671","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}
In recent years, the use of sodium-ion based solid polymer electrolyte (SPE) in energy storage applications has been attracting attention in research. However, SPEs are still suffering from lower ionic conductivity in room temperature, and sodium-ion based SPEs are not yet on par with lithium-ion based SPEs in terms of the overall performance. Therefore, understanding the conduction mechanism of a sodium-ion based SPE is crucial to design and optimize the performance of a sodium-ion based device. Herein, partially hydrolyzed PVA-based SPE was prepared with NaPF6. From the power law region of the plotted AC conductivity graph, the frequency exponent value, s is calculated to be s < 1. The decreasing of s value when temperature increases also suggests that the SPE system follows the Correlated Barrier Hopping (CBH) model where ions conduct through correlated hopping between sites by overcoming barrier heights or potential wells, with conductivity being dependent on both temperature and frequency. The SPE with PVA:NaPF6 ratio of 60:40 (PVA60) exhibits the highest room temperature ionic conductivity of 3.65 × 10−5 S/cm, and has the lowest calculated activation energy of 0.149 eV. FTIR spectra confirmed the complexation of PVA and NaPF6 at certain functional groups, and deconvolution at the 800-900 cm-1 region was done to find out the free-ions and ion-pairs percentage. The degree of crystallinity is also determined from the XRD data where PVA60 exhibits the lowest degree of crystallinity. The TGA and LSV results are also analyzed to provide an overall insight into the thermal and electrochemical stability of the samples.
{"title":"Correlated Barrier Hopping Dynamics of Na+ Ions in Poly(vinyl alcohol) Biopolymer-based Solid Polymer Electrolytes: Electrical and Structural Analysis","authors":"Jacky Yong, Yung-Chung Chen, Shujahadeen B. Aziz, Mayeen Uddin Khandaker, Haw Jiunn Woo","doi":"10.1016/j.electacta.2024.145610","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145610","url":null,"abstract":"In recent years, the use of sodium-ion based solid polymer electrolyte (SPE) in energy storage applications has been attracting attention in research. However, SPEs are still suffering from lower ionic conductivity in room temperature, and sodium-ion based SPEs are not yet on par with lithium-ion based SPEs in terms of the overall performance. Therefore, understanding the conduction mechanism of a sodium-ion based SPE is crucial to design and optimize the performance of a sodium-ion based device. Herein, partially hydrolyzed PVA-based SPE was prepared with NaPF<sub>6</sub>. From the power law region of the plotted AC conductivity graph, the frequency exponent value, <em>s</em> is calculated to be <em>s</em> < 1. The decreasing of <em>s</em> value when temperature increases also suggests that the SPE system follows the Correlated Barrier Hopping (CBH) model where ions conduct through correlated hopping between sites by overcoming barrier heights or potential wells, with conductivity being dependent on both temperature and frequency. The SPE with PVA:NaPF<sub>6</sub> ratio of 60:40 (PVA60) exhibits the highest room temperature ionic conductivity of 3.65 × 10<sup>−5</sup> S/cm, and has the lowest calculated activation energy of 0.149 eV. FTIR spectra confirmed the complexation of PVA and NaPF<sub>6</sub> at certain functional groups, and deconvolution at the 800-900 cm<sup>-1</sup> region was done to find out the free-ions and ion-pairs percentage. The degree of crystallinity is also determined from the XRD data where PVA60 exhibits the lowest degree of crystallinity. The TGA and LSV results are also analyzed to provide an overall insight into the thermal and electrochemical stability of the samples.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"10 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888839","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 : 2024-12-29DOI: 10.1016/j.electacta.2024.145612
Brohath Amrithraj, Andrew Grindal, Gisele Azimi
Aluminum-ion batteries (AIBs) with graphitic cathodes are a scalable energy storage technology, known for their long cycle life, high average discharge voltage, and energy efficiency. Despite significant progress in aluminum graphite batteries (AGB) research, guidelines for engineering optimal cathode morphology remain absent. The meta-analysis in this study addresses this need by evaluating the impact of six morphological features—crystallite sizes (Lc, La), interlayer spacing (d(002)), specific surface area (SSA), specific pore volume (SPV), and particle size (PS)—on various mechanistic and performance metrics of AGBs. Using three experimental cathodes (natural graphite, sonicated graphite, and graphene nanoplatelets) alongside data from over 30 prior studies, linear regression analysis is conducted to identify correlations between morphological characteristics and performance outcomes. The analysis yielded several key findings. First, AGBs exhibit five distinct oxidation and reduction peaks, and voltage shifts were observed across different cathode materials. However, these shifts showed no significant correlation with morphology, suggesting additional factors influence peak voltage. Second, asymmetry in pseudocapacitive and diffusive contributions, combined with anomalies in Dunn's and Lindstrom's coefficients, provides quantitative evidence of reversible (de-)exfoliation in the graphite during cycling. This structural evolution likely influences the dynamic formation of active sites. Third, unexpectedly, no significant correlation was found between morphological features and long-term stable capacities. This may be due to unrecorded variables, such as synthesis details or other unconsidered effects during testing. Fourth, regarding surface area and voltage: a strong negative correlation was observed between surface area (SSA) and pore volume (SPV) with both average charge and discharge voltages, attributed to the enhancement of pseudocapacitive behavior with increased surface area. Additional findings suggest that particle size is correlated with peak voltage shifts and pseudocapacitive/diffusive contributions, although data limitations (n ≤ 4) restricted definitive conclusions. Based on these results, we recommend that future AGB studies include particle size as a parameter for cathode optimization, employ standardized testing conditions, and improve reporting on synthesis and experimental details to enhance comparability. Furthermore, cyclic voltammetry results indicate a need for fundamental studies on the electron transfer mechanisms within AGBs, particularly regarding the five identified reactions. This meta-analysis offers a comprehensive framework for advancing AGB research, proposing insights and best practices to guide the systematic optimization and understanding of this promising technology.
{"title":"Evaluating the Influence of Graphitic Cathode Morphology on the Mechanisms and Performance of Aluminum-Ion Batteries in AlCl3/EMIMCl Electrolyte (r=1.3)","authors":"Brohath Amrithraj, Andrew Grindal, Gisele Azimi","doi":"10.1016/j.electacta.2024.145612","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145612","url":null,"abstract":"Aluminum-ion batteries (AIBs) with graphitic cathodes are a scalable energy storage technology, known for their long cycle life, high average discharge voltage, and energy efficiency. Despite significant progress in aluminum graphite batteries (AGB) research, guidelines for engineering optimal cathode morphology remain absent. The meta-analysis in this study addresses this need by evaluating the impact of six morphological features—crystallite sizes (L<sub>c</sub>, L<sub>a</sub>), interlayer spacing (d(002)), specific surface area (SSA), specific pore volume (SPV), and particle size (PS)—on various mechanistic and performance metrics of AGBs. Using three experimental cathodes (natural graphite, sonicated graphite, and graphene nanoplatelets) alongside data from over 30 prior studies, linear regression analysis is conducted to identify correlations between morphological characteristics and performance outcomes. The analysis yielded several key findings. First, AGBs exhibit five distinct oxidation and reduction peaks, and voltage shifts were observed across different cathode materials. However, these shifts showed no significant correlation with morphology, suggesting additional factors influence peak voltage. Second, asymmetry in pseudocapacitive and diffusive contributions, combined with anomalies in Dunn's and Lindstrom's coefficients, provides quantitative evidence of reversible (de-)exfoliation in the graphite during cycling. This structural evolution likely influences the dynamic formation of active sites. Third, unexpectedly, no significant correlation was found between morphological features and long-term stable capacities. This may be due to unrecorded variables, such as synthesis details or other unconsidered effects during testing. Fourth, regarding surface area and voltage: a strong negative correlation was observed between surface area (SSA) and pore volume (SPV) with both average charge and discharge voltages, attributed to the enhancement of pseudocapacitive behavior with increased surface area. Additional findings suggest that particle size is correlated with peak voltage shifts and pseudocapacitive/diffusive contributions, although data limitations (n ≤ 4) restricted definitive conclusions. Based on these results, we recommend that future AGB studies include particle size as a parameter for cathode optimization, employ standardized testing conditions, and improve reporting on synthesis and experimental details to enhance comparability. Furthermore, cyclic voltammetry results indicate a need for fundamental studies on the electron transfer mechanisms within AGBs, particularly regarding the five identified reactions. This meta-analysis offers a comprehensive framework for advancing AGB research, proposing insights and best practices to guide the systematic optimization and understanding of this promising technology.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"35 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888840","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}
Utilizing redox additive modified electrolyte with 2-methylimidazole cobalt salt (ZIF 67) based electrodes leads to high performance battery capacitor hybrid device. The porous ZIF 67 and its composites with different forms of carbon viz., reduced graphene oxide (rGO) and carbon nanosphere (CNS) were synthesized. The enhanced electrical conductivity of ZIF 67 and rGO composite contributes to faster charge transfer kinetics, resulting in superior electrochemical performance. The performance is further enhanced via electrolyte modification by introducing potassium ferricyanide (KFCN) as a redox additive in aqueous solution of AlCl3. The introduction of redox additive into an aqueous electrolyte result in a significant improvement in the diffusive behaviour, which indicates the battery type charge storage characteristics of the electrode material. The specific capacitance of ZIF 67_rGO composite can easily deliver specific capacitance of ∼350 F g−1, at current density of 1 A g−1, alongwith good cycling because of modifications near the electrode-electrolyte interfaces. Aluminium-ion (Al-ion) based battery supercapacitor hybrid device is assembled by using ZIF 67_rGO and activated carbon in redox additive modified electrolyte, which exhibits an excellent energy density of 18 Wh kg−1 with a power density of 0.52 kW kg−1.
{"title":"Modulating Interfacial Interactions by Using Redox Additives Alongwith Carbon Decorated ZIF-67 Electrodes for Efficient Al-ion Based Battery Supercapacitor Hybrids","authors":"Shyamal Shegokar, Lalit Bharti, Satvik Anshu, Surbhi Priya, Alok K Srivastava, Amreesh Chandra","doi":"10.1016/j.electacta.2024.145611","DOIUrl":"https://doi.org/10.1016/j.electacta.2024.145611","url":null,"abstract":"Utilizing redox additive modified electrolyte with 2-methylimidazole cobalt salt (ZIF 67) based electrodes leads to high performance battery capacitor hybrid device. The porous ZIF 67 and its composites with different forms of carbon viz., reduced graphene oxide (rGO) and carbon nanosphere (CNS) were synthesized. The enhanced electrical conductivity of ZIF 67 and rGO composite contributes to faster charge transfer kinetics, resulting in superior electrochemical performance. The performance is further enhanced via electrolyte modification by introducing potassium ferricyanide (KFCN) as a redox additive in aqueous solution of AlCl<sub>3</sub>. The introduction of redox additive into an aqueous electrolyte result in a significant improvement in the diffusive behaviour, which indicates the battery type charge storage characteristics of the electrode material. The specific capacitance of ZIF 67_rGO composite can easily deliver specific capacitance of ∼350 F g<sup>−1</sup>, at current density of 1 A g<sup>−1</sup>, alongwith good cycling because of modifications near the electrode-electrolyte interfaces. Aluminium-ion (Al-ion) based battery supercapacitor hybrid device is assembled by using ZIF 67_rGO and activated carbon in redox additive modified electrolyte, which exhibits an excellent energy density of 18 Wh kg<sup>−1</sup> with a power density of 0.52 kW kg<sup>−1</sup>.","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"54 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888842","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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