Pub Date : 2025-02-25DOI: 10.1016/j.electacta.2025.145920
Shamshad Ali , Jicheng Jiang , Can Guo , Donghuang Wang , Xin Wang , Weiwei Xia , Maosen Fu , Zaifang Yuan , Wenchao Yan , Jingze Li , Yongqi Zhang , Aijun Zhou
This paper investigates the hydrated and dehydrated phases of cubic and monoclinic Na2Mn[Fe(CN)6], focusing on the impact of crystal water on their electrochemical, structural, and volumetric properties. Interstitial and coordination water impact these materials differently. Removing water increases the coulombic attraction between Na+ and N−, reducing ∠Mn-N-C and ∠Fe-C-N angles and decreasing volume. The densification effect is more pronounced in the monoclinic sample due to its higher sodium content. The dehydrated cubic sample (PW-DH-C) has better cycling stability than the monoclinic sample (PW-DH-MC). The reduced cycling stability in PW-DH-MC is due to its denser rhombohedral structure, resulting from its higher sodium content, which affects the ∠Mn-N-C and ∠Fe-C-N angles. Dehydration triggers Jahn-Teller distortion in Mn3+ ions, inducing reversible rhombohedral-to-tetragonal phase transitions during cycling. After 200 cycles, the capacity retention of the dehydrated cubic sample improves to 59 % when exposed to air and reabsorbing moisture, compared to 50 % in its dehydrated state. Similarly, the dehydrated monoclinic sample shows an increase in retention to 28 %, up from 20 % in its dry condition. Additionally, PW-DH-C experiences lower volumetric changes during cycling, attributed to fewer sodium ions and more Fe(CN)64− vacancies. These findings highlight water's crucial role in optimizing Na2Mn[Fe(CN)6] performance for practical applications.
{"title":"The role of crystal water in the electrochemical properties of sodium manganese hexacyanoferrate cathodes in sodium-ion batteries","authors":"Shamshad Ali , Jicheng Jiang , Can Guo , Donghuang Wang , Xin Wang , Weiwei Xia , Maosen Fu , Zaifang Yuan , Wenchao Yan , Jingze Li , Yongqi Zhang , Aijun Zhou","doi":"10.1016/j.electacta.2025.145920","DOIUrl":"10.1016/j.electacta.2025.145920","url":null,"abstract":"<div><div>This paper investigates the hydrated and dehydrated phases of cubic and monoclinic Na<sub>2</sub>Mn[Fe(CN)<sub>6</sub>], focusing on the impact of crystal water on their electrochemical, structural, and volumetric properties. Interstitial and coordination water impact these materials differently. Removing water increases the coulombic attraction between Na<sup>+</sup> and N<sup>−</sup>, reducing ∠Mn-N-C and ∠Fe-C-N angles and decreasing volume. The densification effect is more pronounced in the monoclinic sample due to its higher sodium content. The dehydrated cubic sample (PW-DH-C) has better cycling stability than the monoclinic sample (PW-DH-MC). The reduced cycling stability in PW-DH-MC is due to its denser rhombohedral structure, resulting from its higher sodium content, which affects the ∠Mn-N-C and ∠Fe-C-N angles. Dehydration triggers Jahn-Teller distortion in Mn<sup>3+</sup> ions, inducing reversible rhombohedral-to-tetragonal phase transitions during cycling. After 200 cycles, the capacity retention of the dehydrated cubic sample improves to 59 % when exposed to air and reabsorbing moisture, compared to 50 % in its dehydrated state. Similarly, the dehydrated monoclinic sample shows an increase in retention to 28 %, up from 20 % in its dry condition. Additionally, PW-DH-C experiences lower volumetric changes during cycling, attributed to fewer sodium ions and more Fe(CN)<sub>6</sub><sup>4−</sup> vacancies. These findings highlight water's crucial role in optimizing Na<sub>2</sub>Mn[Fe(CN)<sub>6</sub>] performance for practical applications.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145920"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143485979","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 : 2025-02-25DOI: 10.1016/j.electacta.2025.145927
Roshan Nazir
Electrocatalytic nitrogen reduction (ENRR) is a green and versatile approach to reduce atmospheric nitrogen into ammonia. This promising approach however lacks inexpensive and efficient electrocatalyst that promotes scalable ammonia production. Herein, we present a non-precious, mesoporous NiFe2O4 nanosheets (m-NiFe2O4 NS) prepared via a simple solution combustion method for the ENRR. The synthesized m-NiFe2O4 NS showed an outstanding NH3 yield of 45 μgh−1mgcat-1, TOF of 0.618h-1, and Faradaic efficiency of 12 % at a potential of -0.4 V vs. RHE. This activity of m-NiFe2O4 NS is attributed to highly porous structure, and the presence of Fe and Ni atoms, where Fe atoms active sites promotes N2 activation, polarization, and boosts ENRR activity and Ni atoms protects ENRR active sites on Fe for competing HER and makes them exclusively available for ENRR. In this work, we proposed enzymatic pathway mechanism based on in-situ Raman investigations. That revealed the formation of *N2H and *N2H2 type intermediates during ammonia formation. The preliminary step is N2 adsorption on the active sites (metal centres and surface defects) of m-NiFe2O4NS followed by proton coupled electron transfer reactions (PCET) that generates*N2H and *N2H2 type intermediates which then undergoes series of PCETs to generate NH3.
{"title":"Fe dominated and O-vac rich mesoporous NiFe2O4 for enhanced electrocatalytic Nitrogen reduction to ammonia through enzymatic pathway","authors":"Roshan Nazir","doi":"10.1016/j.electacta.2025.145927","DOIUrl":"10.1016/j.electacta.2025.145927","url":null,"abstract":"<div><div>Electrocatalytic nitrogen reduction (ENRR) is a green and versatile approach to reduce atmospheric nitrogen into ammonia. This promising approach however lacks inexpensive and efficient electrocatalyst that promotes scalable ammonia production. Herein, we present a non-precious, mesoporous NiFe<sub>2</sub>O<sub>4</sub> nanosheets (m-NiFe<sub>2</sub>O<sub>4</sub> NS) prepared via a simple solution combustion method for the ENRR. The synthesized m-NiFe<sub>2</sub>O<sub>4</sub> NS showed an outstanding NH<sub>3</sub> yield of 45 μgh<sup>−1</sup>mg<sub>cat</sub><sup>-1</sup>, TOF of 0.618h<sup>-1</sup>, and Faradaic efficiency of 12 % at a potential of -0.4 V vs. RHE. This activity of m-NiFe<sub>2</sub>O<sub>4</sub> NS is attributed to highly porous structure, and the presence of Fe and Ni atoms, where Fe atoms active sites promotes N<sub>2</sub> activation, polarization, and boosts ENRR activity and Ni atoms protects ENRR active sites on Fe for competing HER and makes them exclusively available for ENRR. In this work, we proposed enzymatic pathway mechanism based on in-situ Raman investigations. That revealed the formation of *N<sub>2</sub>H and *N<sub>2</sub>H<sub>2</sub> type intermediates during ammonia formation. The preliminary step is N<sub>2</sub> adsorption on the active sites (metal centres and surface defects) of m-NiFe<sub>2</sub>O<sub>4</sub>NS followed by proton coupled electron transfer reactions (PCET) that generates*N<sub>2</sub>H and *N<sub>2</sub>H<sub>2</sub> type intermediates which then undergoes series of PCETs to generate NH<sub>3</sub>.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145927"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486040","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}
Oxygen reduction is the critical step in advanced chlor-alkali electrolysis, which has motivated extensive research in catalyst development for improved efficiency and durability. This study investigates the oxygen reduction reaction (ORR) on Cu-based electrocatalysts supported on N-doped carbon (Cu/NC), derived from a Cu-modified zeolitic imidazolate framework (ZIF), and their ultimate performance in a chlor-alkali electrolyzer. Through comprehensive electrochemical characterization in 0.1 M NaOH solution, values of Eonset = 0.87 V and E1/2 = 0.75 V (vs. RHE) were obtained, which are competitive with commercial Pt/C despite the superior j achieved by the latter in LSV tests. The electron transfer number (n) of the optimum Cu/NC was 4, very close to benchmark catalyst Pt/C 20 wt. % (n = 3.94). Cu/NC had a low Tafel slope (128 mV dec−1), thus speeding up the ORR on this nanocatalyst. Additionally, chronoamperometry and accelerated durability tests demonstrated the long-term stability of Cu/NC for 10 h. The catalyst was assembled as an oxygen depolarized cathode (ODC) in a purpose-designed advanced chlor-alkali electrolyzer, resulting in a cell voltage of 2.1 V at 1 kA m-2 and 80 °C, which underscores the potential of Cu-based nanocatalysts in electrochemical energy devices. This research serves to leverage insights for the use of advanced electrocatalysts to enhance the efficiency and sustainability of chlor-alkali electrolysis.
{"title":"Integration of a non-precious pyrolyzed Cu-doped ZIF as an oxygen depolarized cathode in an advanced chlor-alkali electrolyzer","authors":"Tahereh Jangjooye Shaldehi , Lele Zhao , Teresa Andreu , Soosan Rowshanzamir , Ignasi Sirés","doi":"10.1016/j.electacta.2025.145929","DOIUrl":"10.1016/j.electacta.2025.145929","url":null,"abstract":"<div><div>Oxygen reduction is the critical step in advanced chlor-alkali electrolysis, which has motivated extensive research in catalyst development for improved efficiency and durability. This study investigates the oxygen reduction reaction (ORR) on Cu-based electrocatalysts supported on N-doped carbon (Cu/NC), derived from a Cu-modified zeolitic imidazolate framework (ZIF), and their ultimate performance in a chlor-alkali electrolyzer. Through comprehensive electrochemical characterization in 0.1 M NaOH solution, values of <em>E</em><sub>onset</sub> = 0.87 V and <em>E</em><sub>1/</sub><sub>2</sub> = 0.75 V (<em>vs.</em> RHE) were obtained, which are competitive with commercial Pt/C despite the superior <em>j</em> achieved by the latter in LSV tests. The electron transfer number (<em>n</em>) of the optimum Cu/NC was 4, very close to benchmark catalyst Pt/C 20 wt. % (<em>n</em> = 3.94). Cu/NC had a low Tafel slope (128 mV dec<sup>−1</sup>), thus speeding up the ORR on this nanocatalyst. Additionally, chronoamperometry and accelerated durability tests demonstrated the long-term stability of Cu/NC for 10 h. The catalyst was assembled as an oxygen depolarized cathode (ODC) in a purpose-designed advanced chlor-alkali electrolyzer, resulting in a cell voltage of 2.1 V at 1 kA m<sup>-2</sup> and 80 °C, which underscores the potential of Cu-based nanocatalysts in electrochemical energy devices. This research serves to leverage insights for the use of advanced electrocatalysts to enhance the efficiency and sustainability of chlor-alkali electrolysis.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"522 ","pages":"Article 145929"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495851","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 : 2025-02-25DOI: 10.1016/j.electacta.2025.145928
Zeferino S.B. Pedro, Joseany M.S. Almeida, Christopher M.A. Brett
Polymer films were formed from a triarylmethane redox dye, brilliant green (BG) by electropolymerization on glassy carbon electrodes (GCE) modified with multiwalled carbon nanotubes (MWCNT) using potential cycling in glyceline deep eutectic solvent, formed by choline chloride (ChCl), and glycerol (G) 1:2 molar ratio with 5 % added water, with addition of different acid dopants. Electropolymerization was also carried out on unmodified GCE for comparison. The modified electrode, PBG/MWCNT/GCE, was characterized by cyclic voltammetry in 0.1 M Britton-Robinson buffer at pH 3, electrochemical impedance spectroscopy and the morphology of its surface by scanning electron microscopy. The best electrochemical behaviour was obtained with a polymerization scan rate of 100 mV s−1. The polymer modified electrode was used for the determination of epinephrine using differential pulse voltammetry. The linear range was 5 µM to 50 µM with a detection limit of 0.7 µM. The sensor was tested on pharmaceutical and urine samples successfully with good reproducibility and repeatability.
{"title":"Influence of deep eutectic solvent and water mixtures on the electropolymerization of brilliant green on nanotube modified electrodes for the electrochemical determination of epinephrine","authors":"Zeferino S.B. Pedro, Joseany M.S. Almeida, Christopher M.A. Brett","doi":"10.1016/j.electacta.2025.145928","DOIUrl":"10.1016/j.electacta.2025.145928","url":null,"abstract":"<div><div>Polymer films were formed from a triarylmethane redox dye, brilliant green (BG) by electropolymerization on glassy carbon electrodes (GCE) modified with multiwalled carbon nanotubes (MWCNT) using potential cycling in glyceline deep eutectic solvent, formed by choline chloride (ChCl), and glycerol (G) 1:2 molar ratio with 5 % added water, with addition of different acid dopants. Electropolymerization was also carried out on unmodified GCE for comparison. The modified electrode, PBG/MWCNT/GCE, was characterized by cyclic voltammetry in 0.1 M Britton-Robinson buffer at pH 3, electrochemical impedance spectroscopy and the morphology of its surface by scanning electron microscopy. The best electrochemical behaviour was obtained with a polymerization scan rate of 100 mV s<sup>−1</sup>. The polymer modified electrode was used for the determination of epinephrine using differential pulse voltammetry. The linear range was 5 µM to 50 µM with a detection limit of 0.7 µM. The sensor was tested on pharmaceutical and urine samples successfully with good reproducibility and repeatability.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145928"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.electacta.2025.145935
Guanhua Yang , Jie Zhang , Zhiguo Zhang , Xianling Qin , Quansheng Teng , Huwei Hao , Zhiqing Zhang , Xueyou Tan , Qingyu Li , Hongqiang Wang
Hard carbon materials synthesized from biomass precursors exhibit the excellent characteristics of high capacity, cost-effectiveness and wide-ranging availability. In this study, the aniline-functionalized hard carbon material (HC-P-F) with porous spherical morphology was prepared successfully by enzymatic hydrolysis combing with “burying” heat treatment and diazotization reaction using taro starch as carbon source. The HC-P-F possesses porous morphology, which can shorten the ion transport path, thereby increasing the ion transport rate, and also providing more active sites for Na+ storage. At the same time, the aniline radical grafting on the surface of the hard carbon materials helps to improve the battery life and cycle stability. The porous spherical structure and surface functionalization produce a good synergistic effect, increasing the specific surface area, enhancing the stability of the cycle, improving the electrical conductivity and promoting the rapid insertion and removal of ions of the hard carbon material. The results show that the HC-P-F maintains a high reversible specific capacity of 260.19 mAh g-1 after 300 cycles at 0.5 A g-1. And it displays excellent rate performance with an average reversible specific capacity of 358.5, 338.39, 308.32, 276.86, 231.61 and 120.46 mAh g-1 at 0.1, 0.2, 0.5, 1, 2 and 5 A g-1, respectively. Furthermore, the HC-P-F exhibits lower impedance, significant capacitive behavior dominated by pseudocapacitance contribution and faster sodium ion interface dynamics comparing with other hard carbon materials. In addition, when assembled into full cell with commercial sodium vanadate (NVP), it demonstrates exceptional cycling stability with a high energy density of 184.06 Wh kg-1 after 300 cycles at 0.5 A g-1. This successful preparation of the aniline-functionalized hard carbon materials provides another solution for improving the electrochemical properties of the anode electrode materials, which would promote the application research of starch-based hard carbon anode materials in sodium ion batteries (SIBs).
{"title":"Surface functionalized porous spherical hard carbon material derived from taro starch for high performance sodium storage","authors":"Guanhua Yang , Jie Zhang , Zhiguo Zhang , Xianling Qin , Quansheng Teng , Huwei Hao , Zhiqing Zhang , Xueyou Tan , Qingyu Li , Hongqiang Wang","doi":"10.1016/j.electacta.2025.145935","DOIUrl":"10.1016/j.electacta.2025.145935","url":null,"abstract":"<div><div>Hard carbon materials synthesized from biomass precursors exhibit the excellent characteristics of high capacity, cost-effectiveness and wide-ranging availability. In this study, the aniline-functionalized hard carbon material (HC-P-F) with porous spherical morphology was prepared successfully by enzymatic hydrolysis combing with “burying” heat treatment and diazotization reaction using taro starch as carbon source. The HC-P-F possesses porous morphology, which can shorten the ion transport path, thereby increasing the ion transport rate, and also providing more active sites for Na<sup>+</sup> storage. At the same time, the aniline radical grafting on the surface of the hard carbon materials helps to improve the battery life and cycle stability. The porous spherical structure and surface functionalization produce a good synergistic effect, increasing the specific surface area, enhancing the stability of the cycle, improving the electrical conductivity and promoting the rapid insertion and removal of ions of the hard carbon material. The results show that the HC-P-F maintains a high reversible specific capacity of 260.19 mAh g<sup>-1</sup> after 300 cycles at 0.5 A g<sup>-1</sup>. And it displays excellent rate performance with an average reversible specific capacity of 358.5, 338.39, 308.32, 276.86, 231.61 and 120.46 mAh g<sup>-1</sup> at 0.1, 0.2, 0.5, 1, 2 and 5 A g<sup>-1</sup>, respectively. Furthermore, the HC-P-F exhibits lower impedance, significant capacitive behavior dominated by pseudocapacitance contribution and faster sodium ion interface dynamics comparing with other hard carbon materials. In addition, when assembled into full cell with commercial sodium vanadate (NVP), it demonstrates exceptional cycling stability with a high energy density of 184.06 Wh kg<sup>-1</sup> after 300 cycles at 0.5 A g<sup>-1</sup>. This successful preparation of the aniline-functionalized hard carbon materials provides another solution for improving the electrochemical properties of the anode electrode materials, which would promote the application research of starch-based hard carbon anode materials in sodium ion batteries (SIBs).</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145935"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486038","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 : 2025-02-25DOI: 10.1016/j.electacta.2025.145930
Salma Hafed-Khatiri , David Salinas-Torres , Francisco Montilla
This research work presents a straightforward electrochemical method to assess acetylcholinesterase (AChE) catalytic activity in the marine environment, which is directly affected by the presence of pollutants. Such an electrochemical approach consists of using p-acetoxyphenol, whose hydrolysis is akin to that of acetylcholine and monitoring the electroactive product (hydroquinone). Despite structural alterations of AChE in synthetic seawater revealed by fluorescence measurements, the enzyme's folded state is stable. This enzyme's stability together with its performance in the selected medium determines its capacity for marine monitoring applications. As proof of concept, the inhibitory effects of an organophosphate pesticide (malathion) on AChE activity were performed, confirming that malathion meaningfully inhibited the AChE enzymatic activity. Overall, this electrochemical approach provides a robust platform for real-time monitoring of AChE activity in marine ecosystems. The findings underscore its potential for developing biosensors to monitor neurotoxic contaminants, offering a valuable tool for environmental protection and marine monitoring.
{"title":"Assessing acetylcholinesterase catalytic activity in the marine environment","authors":"Salma Hafed-Khatiri , David Salinas-Torres , Francisco Montilla","doi":"10.1016/j.electacta.2025.145930","DOIUrl":"10.1016/j.electacta.2025.145930","url":null,"abstract":"<div><div>This research work presents a straightforward electrochemical method to assess acetylcholinesterase (AChE) catalytic activity in the marine environment, which is directly affected by the presence of pollutants. Such an electrochemical approach consists of using <em>p</em>-acetoxyphenol, whose hydrolysis is akin to that of acetylcholine and monitoring the electroactive product (hydroquinone). Despite structural alterations of AChE in synthetic seawater revealed by fluorescence measurements, the enzyme's folded state is stable. This enzyme's stability together with its performance in the selected medium determines its capacity for marine monitoring applications. As proof of concept, the inhibitory effects of an organophosphate pesticide (malathion) on AChE activity were performed, confirming that malathion meaningfully inhibited the AChE enzymatic activity. Overall, this electrochemical approach provides a robust platform for real-time monitoring of AChE activity in marine ecosystems. The findings underscore its potential for developing biosensors to monitor neurotoxic contaminants, offering a valuable tool for environmental protection and marine monitoring.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145930"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495848","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 : 2025-02-24DOI: 10.1016/j.electacta.2025.145915
Dongfeng Sun , Jiaxin Liu , Pengpeng Qiang , Wanquan Ma , Yanning Qu , Shukai Ding , Yu Yuan , Zhiru Li , Bingshe Xu
Designing efficient water splitting electrocatalysts in alkaline electrolytes is crucial but also presents significant challenges. In this study, Co2P/MoP/CC catalysts were synthesized using a hydrothermal method and in situ phosphorization with carbon cloth as the substrate. This unique porous octahedral structure features large specific surface area, exposing more active sites and aiding in bubble transportation. At a current density of 10 mA/cm², the overpotentials for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are 86 mV and 280 mV, respectively. This excellent performance is attributed to the formation of a Co2P/MoP heterojunction, which promotes electron transfer and enhances the adsorption strength of intermediates. In the overall water splitting experiment, only a low potential of 1.65 V is required to reach 10 mA/cm² and maintain stability for 100,000 seconds. This study offers a novel strategy for the development of efficient water electrolysis catalysts.
{"title":"Construction and modulation of Co2P/MoP/CC heterojunction with porous octahedral structure to improve the Overall Water Splitting capacity","authors":"Dongfeng Sun , Jiaxin Liu , Pengpeng Qiang , Wanquan Ma , Yanning Qu , Shukai Ding , Yu Yuan , Zhiru Li , Bingshe Xu","doi":"10.1016/j.electacta.2025.145915","DOIUrl":"10.1016/j.electacta.2025.145915","url":null,"abstract":"<div><div>Designing efficient water splitting electrocatalysts in alkaline electrolytes is crucial but also presents significant challenges. In this study, Co<sub>2</sub>P/MoP/CC catalysts were synthesized using a hydrothermal method and in situ phosphorization with carbon cloth as the substrate. This unique porous octahedral structure features large specific surface area, exposing more active sites and aiding in bubble transportation. At a current density of 10 mA/cm², the overpotentials for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are 86 mV and 280 mV, respectively. This excellent performance is attributed to the formation of a Co<sub>2</sub>P/MoP heterojunction, which promotes electron transfer and enhances the adsorption strength of intermediates. In the overall water splitting experiment, only a low potential of 1.65 V is required to reach 10 mA/cm² and maintain stability for 100,000 seconds. This study offers a novel strategy for the development of efficient water electrolysis catalysts.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145915"},"PeriodicalIF":5.5,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143477517","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 : 2025-02-24DOI: 10.1016/j.electacta.2025.145916
Jaanus Eskusson, Enn Lust, Alar Jänes
The increasing concern on the safety risks associated with the flammable organic electrolytes in alkali-ion batteries and the pursuit of both high energy density and power density in one device has spurred the investigation of aqueous multivalent metal ion capacitors. Zinc-ion capacitors (ZICs) have the advantages of low standard potential, high theoretical capacity and good safety in aqueous electrolytes. We demonstrated that a cost effective and high energy density Zn-ion based capacitors, using Zn as the negative electrode, activated carbon fabric as the positive electrode and Zn cation based 1 molar (M) ZnSO4, Zn(BF4)2, Zn(ClO4)2, Zn(TFSI)2 or Zn(OTf)2 aqueous and non-aqueous electrolytes (acetonitrile (AN), and propylene carbonate (PC)) are possible. Very high energy and power densities (32 Wh kg−1 at 20 kW kg−1) have been calculated for aqueous Zn(ClO4)2 and Zn(BF4)2 based Zn-ion capacitors. Some assembled ZICs (in particular based on Zn(BF4)2 and Zn(OTf)2 aqueous electrolytes) had shown excellent cycling and energy stability over 10,000 cycles without measurable capacity loss. High energy densities (80 Wh kg−1) have been calculated for 1 M Zn(BF4)2/AN based Zn-ion capacitors. Very good electrochemical stability after 3000 cycles of cells has been achieved demonstrating reasonably high energy efficiency value (66.8 %) for Zn(TFSI)2/AN based ZIC cell. The energy efficiency measurable decreased in the order electrolytes: Zn(TFSI)2/AN > Zn(BF4)2/PC > Zn(TFSI)2/PC > Zn(OTf)2/AN > Zn(BF4)2/AN.
{"title":"Zn-ion capacitors based on solutions of different electrolytes","authors":"Jaanus Eskusson, Enn Lust, Alar Jänes","doi":"10.1016/j.electacta.2025.145916","DOIUrl":"10.1016/j.electacta.2025.145916","url":null,"abstract":"<div><div>The increasing concern on the safety risks associated with the flammable organic electrolytes in alkali-ion batteries and the pursuit of both high energy density and power density in one device has spurred the investigation of aqueous multivalent metal ion capacitors. Zinc-ion capacitors (ZICs) have the advantages of low standard potential, high theoretical capacity and good safety in aqueous electrolytes. We demonstrated that a cost effective and high energy density Zn-ion based capacitors, using Zn as the negative electrode, activated carbon fabric as the positive electrode and Zn cation based 1 molar (M) ZnSO<sub>4</sub>, Zn(BF<sub>4</sub>)<sub>2</sub>, Zn(ClO<sub>4</sub>)<sub>2</sub>, Zn(TFSI)<sub>2</sub> or Zn(OTf)<sub>2</sub> aqueous and non-aqueous electrolytes (acetonitrile (AN), and propylene carbonate (PC)) are possible. Very high energy and power densities (32 Wh kg<sup>−1</sup> at 20 kW kg<sup>−1</sup>) have been calculated for aqueous Zn(ClO<sub>4</sub>)<sub>2</sub> and Zn(BF<sub>4</sub>)<sub>2</sub> based Zn-ion capacitors. Some assembled ZICs (in particular based on Zn(BF<sub>4</sub>)<sub>2</sub> and Zn(OTf)<sub>2</sub> aqueous electrolytes) had shown excellent cycling and energy stability over 10,000 cycles without measurable capacity loss. High energy densities (80 Wh kg<sup>−1</sup>) have been calculated for 1 M Zn(BF<sub>4</sub>)<sub>2</sub>/AN based Zn-ion capacitors. Very good electrochemical stability after 3000 cycles of cells has been achieved demonstrating reasonably high energy efficiency value (66.8 %) for Zn(TFSI)<sub>2</sub>/AN based ZIC cell. The energy efficiency measurable decreased in the order electrolytes: Zn(TFSI)<sub>2</sub>/AN > Zn(BF<sub>4</sub>)<sub>2</sub>/PC > Zn(TFSI)<sub>2</sub>/PC > Zn(OTf)<sub>2</sub>/AN > Zn(BF<sub>4</sub>)<sub>2</sub>/AN.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145916"},"PeriodicalIF":5.5,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143477518","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}
Flow electrode capacitive deionization (FCDI) is an advanced electrochemical technique for water desalination, offering significant energy efficiency, which is increasingly vital in the context of the growing global scarcity of freshwater resources. This study investigates the performance of three operational modes—constant voltage (CV), constant current (CC), and hybrid CV-CC—in FCDI systems. The results show that the CC mode excels in charge efficiency and ion removal capacity, primarily due to its constant current operation that minimizes energy consumption. In contrast, the CV mode enables faster ion adsorption due to its higher applied voltage, facilitating quicker desalination. The hybrid CV-CC mode integrates the strengths of both CV and CC modes, achieving a 25 % increase in salt adsorption capacity compared to the CC mode, while reducing energy consumption by 24–29 % relative to the CV mode. These findings demonstrate the potential of the hybrid operational strategy in optimizing the performance of FCDI systems, offering a promising approach for more energy-efficient and cost-effective water desalination. This work uniquely provides a comparative assessment of CV, CC, and hybrid CV-CC operational modes in FCDI and introduces tortuous-path spacers to enhance mass transfer, offering new insights into optimizing FCDI systems for practical desalination applications.
{"title":"Analysis of flow-electrode capacitive deionization: performance assessment of voltage-driven, current-driven, and hybrid control strategies","authors":"Amin Navapour, Ardalan Ganjizasde, Seyed Nezameddin Ashrafizadeh","doi":"10.1016/j.electacta.2025.145907","DOIUrl":"10.1016/j.electacta.2025.145907","url":null,"abstract":"<div><div>Flow electrode capacitive deionization (FCDI) is an advanced electrochemical technique for water desalination, offering significant energy efficiency, which is increasingly vital in the context of the growing global scarcity of freshwater resources. This study investigates the performance of three operational modes—constant voltage (CV), constant current (CC), and hybrid CV-CC—in FCDI systems. The results show that the CC mode excels in charge efficiency and ion removal capacity, primarily due to its constant current operation that minimizes energy consumption. In contrast, the CV mode enables faster ion adsorption due to its higher applied voltage, facilitating quicker desalination. The hybrid CV-CC mode integrates the strengths of both CV and CC modes, achieving a 25 % increase in salt adsorption capacity compared to the CC mode, while reducing energy consumption by 24–29 % relative to the CV mode. These findings demonstrate the potential of the hybrid operational strategy in optimizing the performance of FCDI systems, offering a promising approach for more energy-efficient and cost-effective water desalination. This work uniquely provides a comparative assessment of CV, CC, and hybrid CV-CC operational modes in FCDI and introduces tortuous-path spacers to enhance mass transfer, offering new insights into optimizing FCDI systems for practical desalination applications.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145907"},"PeriodicalIF":5.5,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143473460","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 : 2025-02-23DOI: 10.1016/j.electacta.2025.145911
Mengmeng Yan , Zi-Ao Jin , Pengji Wang , Yaru Guo , Ya-Xia Yin , Sailong Xu
Transition metal layered oxides have emerged as promising cathodes for sodium-ion batteries (SIBs), yet suffer from sluggish kinetics and serious capacity attenuation due to surface side reactions, microcracks and surface residual alkalies. One effective improvement strategy typically by single surface coating is used to boost electrochemical performances. Here, a dual-surface-coated O3-NaNi0.4Fe0.2Mn0.4O2 (NFM) cathode is prepared using the in-situ formed Na3PO4/P3-NFM during the thermal decomposition reaction of NH4H2PO4. The Na3PO4 coating layer, formed by NH4H2PO4 and the residual sodium species on the surface of O3-NFM, serves as a protective layer; while the P3-NFM, with layered structure anchored firmly on the O3-NFM surface, facilitates fast Na+ diffusion kinetics. The Na3PO4/P3-NFM coatings rebuild the interface as a stable and fast path for Na+ transport, enhance the interface stability, and restrain the adverse factors for interfacial side reactions, intragranular cracks and irreversible phase transformations. Consequently, the optimized cathode exhibits satisfactory rate capabilities (130.6 mAh g−1 at 1C and 90.0 mAh g−1 at 10C), and a favorable cyclability (75.6 % after 300 cycles at 1C), as well as an excellent air stability. These results promise a highly effective improvement strategy for boosting electrochemical performances of promising layered oxide cathodes for SIBs.
{"title":"In situ surface engineering O3-layered oxide cathode via Na3PO4/P3-layered oxide dual coating layers","authors":"Mengmeng Yan , Zi-Ao Jin , Pengji Wang , Yaru Guo , Ya-Xia Yin , Sailong Xu","doi":"10.1016/j.electacta.2025.145911","DOIUrl":"10.1016/j.electacta.2025.145911","url":null,"abstract":"<div><div>Transition metal layered oxides have emerged as promising cathodes for sodium-ion batteries (SIBs), yet suffer from sluggish kinetics and serious capacity attenuation due to surface side reactions, microcracks and surface residual alkalies. One effective improvement strategy typically by single surface coating is used to boost electrochemical performances. Here, a dual-surface-coated O3-NaNi<sub>0.4</sub>Fe<sub>0.2</sub>Mn<sub>0.4</sub>O<sub>2</sub> (NFM) cathode is prepared using the <em>in-situ</em> formed Na<sub>3</sub>PO<sub>4</sub>/P3-NFM during the thermal decomposition reaction of NH<sub>4</sub>H<sub>2</sub>PO<sub>4</sub>. The Na<sub>3</sub>PO<sub>4</sub> coating layer, formed by NH<sub>4</sub>H<sub>2</sub>PO<sub>4</sub> and the residual sodium species on the surface of O3-NFM, serves as a protective layer; while the P3-NFM, with layered structure anchored firmly on the O3-NFM surface, facilitates fast Na<sup>+</sup> diffusion kinetics. The Na<sub>3</sub>PO<sub>4</sub>/P3-NFM coatings rebuild the interface as a stable and fast path for Na<sup>+</sup> transport, enhance the interface stability, and restrain the adverse factors for interfacial side reactions, intragranular cracks and irreversible phase transformations. Consequently, the optimized cathode exhibits satisfactory rate capabilities (130.6 mAh g<sup>−1</sup> at 1C and 90.0 mAh g<sup>−1</sup> at 10C), and a favorable cyclability (75.6 % after 300 cycles at 1C), as well as an excellent air stability. These results promise a highly effective improvement strategy for boosting electrochemical performances of promising layered oxide cathodes for SIBs.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145911"},"PeriodicalIF":5.5,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143477575","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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