Pub Date : 2025-08-04DOI: 10.1016/j.ssi.2025.116967
Alexander Bonkowski, Roger A. De Souza
The study of ion transport in solid-state materials increasingly utilises Molecular Dynamics (MD) simulations in order to interpret experimental data, reveal mechanistic information, and predict the properties of new systems. In this paper, we consider a variety of issues that may produce incorrect results in MD simulations, and thus may lead to unsound conclusions being drawn. Specifically, we discuss how to prepare, perform and analyse MD simulations of ion transport, highlighting some of the most common pitfalls in MD simulations and how to avoid them. In this way, we arrive at selected guidelines that promote the acquisition of reliable ion transport data from MD simulations.
{"title":"From setup to analysis: A compact guide to performing Molecular Dynamics simulations of ion transport in solids","authors":"Alexander Bonkowski, Roger A. De Souza","doi":"10.1016/j.ssi.2025.116967","DOIUrl":"10.1016/j.ssi.2025.116967","url":null,"abstract":"<div><div>The study of ion transport in solid-state materials increasingly utilises Molecular Dynamics (MD) simulations in order to interpret experimental data, reveal mechanistic information, and predict the properties of new systems. In this paper, we consider a variety of issues that may produce incorrect results in MD simulations, and thus may lead to unsound conclusions being drawn. Specifically, we discuss how to prepare, perform and analyse MD simulations of ion transport, highlighting some of the most common pitfalls in MD simulations and how to avoid them. In this way, we arrive at selected guidelines that promote the acquisition of reliable ion transport data from MD simulations.</div></div>","PeriodicalId":431,"journal":{"name":"Solid State Ionics","volume":"429 ","pages":"Article 116967"},"PeriodicalIF":3.3,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144766536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-08-02DOI: 10.1016/j.ssi.2025.116949
Hendrik Wulfmeier , Uliana Yakhnevych , Cornelius Boekhoff , Allan Diima , Marlo Kunzner , Leonard M. Verhoff , Jonas Paul , Julius Ratzenberger , Elke Beyreuther , Joshua Gössel , Iuliia Kiseleva , Michael Rüsing , Simone Sanna , Lukas M. Eng , Holger Fritze
Conductive ferroelectric domain walls (DWs) represent a promising topical system for the development of nanoelectronic components and device sensors to be operational at elevated temperatures. DWs show very different properties as compared to their hosting bulk crystal, in particular with respect to the high local electrical conductivity. The objective of this work is to demonstrate DW conductivity up to temperatures as high as 400 °C which extends previous studies significantly. Experimental investigation of the DW conductivity of charged, inclined DWs is performed using 5 mol % MgO-doped lithium niobate single crystals. Current–voltage ( ) curves are determined by DC electrometer measurements and impedance spectroscopy and found to be identical. Moreover, impedance spectroscopy enables to recognize artifacts such as damaged electrodes. Temperature dependent measurements over repeated heating cycles reveal two distinct thermal activation energies for a given DW, with the higher of the activation energies only measured at higher temperatures. Depending on the specific sample, the higher activation energy is found above 160 °C to 230 °C. This suggests, in turn, that more than one type of defect/polaron is involved, and that the dominant transport mechanism changes with increasing temperature. First principles atomistic modeling suggests that the conductivity of inclined domain walls cannot be solely explained by the formation of a 2D carrier gas and must be supported by hopping processes. This holds true even at temperatures as high as 400 °C. Our investigations underline the potential to extend DW current based nanoelectronic and sensor applications even into the so-far unexplored temperature range up to 400 °C.
{"title":"Demonstration of domain wall current in MgO-doped lithium niobate single crystals up to 400 °C","authors":"Hendrik Wulfmeier , Uliana Yakhnevych , Cornelius Boekhoff , Allan Diima , Marlo Kunzner , Leonard M. Verhoff , Jonas Paul , Julius Ratzenberger , Elke Beyreuther , Joshua Gössel , Iuliia Kiseleva , Michael Rüsing , Simone Sanna , Lukas M. Eng , Holger Fritze","doi":"10.1016/j.ssi.2025.116949","DOIUrl":"10.1016/j.ssi.2025.116949","url":null,"abstract":"<div><div>Conductive ferroelectric domain walls (DWs) represent a promising topical system for the development of nanoelectronic components and device sensors to be operational at elevated temperatures. DWs show very different properties as compared to their hosting bulk crystal, in particular with respect to the high local electrical conductivity. The objective of this work is to demonstrate DW conductivity up to temperatures as high as 400<!--> <!-->°C which extends previous studies significantly. Experimental investigation of the DW conductivity of charged, inclined DWs is performed using 5<!--> <!-->mol<!--> <!-->% MgO-doped lithium niobate single crystals. Current–voltage (<span><math><mrow><mi>I</mi><mi>V</mi></mrow></math></span> <!--> <!-->) curves are determined by DC electrometer measurements and impedance spectroscopy and found to be identical. Moreover, impedance spectroscopy enables to recognize artifacts such as damaged electrodes. Temperature dependent measurements over repeated heating cycles reveal two distinct thermal activation energies for a given DW, with the higher of the activation energies only measured at higher temperatures. Depending on the specific sample, the higher activation energy is found above 160<!--> <!-->°C to 230<!--> <!-->°C. This suggests, in turn, that more than one type of defect/polaron is involved, and that the dominant transport mechanism changes with increasing temperature. First principles atomistic modeling suggests that the conductivity of inclined domain walls cannot be solely explained by the formation of a 2D carrier gas and must be supported by hopping processes. This holds true even at temperatures as high as 400<!--> <!-->°C. Our investigations underline the potential to extend DW current based nanoelectronic and sensor applications even into the so-far unexplored temperature range up to 400<!--> <!-->°C.</div></div>","PeriodicalId":431,"journal":{"name":"Solid State Ionics","volume":"429 ","pages":"Article 116949"},"PeriodicalIF":3.3,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-08-01DOI: 10.1016/j.ssi.2025.116985
Mohan S. , R.F. Bhajantri , B.M. Nagabushana
The optimization of conductivity and stability of bio-solid polymer electrolytes through active functional groups for high-performance lithium batteries has not yet been fully realized. This study focus on fabrication and characterization of biocompatible hydroxypropyl methylcellulose-chitosan (HPMC-Cs) polymer electrolytes, which are plasticized with glycerol, TiO2 nanofillers, and LiClO4 salt. The research employs a solution casting technique, with a sequential optimization of the polymer blend, nanofiller, and salt concentration. XRD analysis confirmed the predominantly amorphous nature of the optimized electrolyte. ATR-FTIR studies revealed the various functional groups associated with polymer nanocomposite electrolyte and demonstrated interactions among components through band shifts. Thermal analysis conducted through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) revealed a glass transition temperature of approximately 40.4 °C, with complete degradation occurring above 300 °C for the polymer electrolyte, comprising 7.5 wt% nanofillers and 12.5 wt% LiClO4 salt. The optimized electrolyte exhibited the highest ionic conductivity of 0.129 mScm−1, an electrochemical stability window of 3.35 V, maximum cationic transference number of 0.70, DC conductivity of 7.94 μS/cm, tensile strength of 3.14 MPa and a maximum strain of 150 %. The structural and electrical relaxation time corresponds to the relaxation behavior of polymer and ions found to decreased to 0.50 μs and 0.03 μs respectively while coupling index drops to 15.55. The evaluation of interfacial resistance over a period of 10 days demonstrates the impact of moisture on interfacial resistance, wherein the resistance initially decreased and subsequently increased and stabilized. These results underscore the potential of this bio-based polymer nanocomposite electrolyte for energy storage applications.
{"title":"Functional group engineered green Hydroxypropyl methylcellulose – Chitosan bio-polymer nanocomposite electrolyte with TiO2 filler and LiClO4 salt.","authors":"Mohan S. , R.F. Bhajantri , B.M. Nagabushana","doi":"10.1016/j.ssi.2025.116985","DOIUrl":"10.1016/j.ssi.2025.116985","url":null,"abstract":"<div><div>The optimization of conductivity and stability of bio-solid polymer electrolytes through active functional groups for high-performance lithium batteries has not yet been fully realized. This study focus on fabrication and characterization of biocompatible hydroxypropyl methylcellulose-chitosan (HPMC-Cs) polymer electrolytes, which are plasticized with glycerol, TiO<sub>2</sub> nanofillers, and LiClO<sub>4</sub> salt. The research employs a solution casting technique, with a sequential optimization of the polymer blend, nanofiller, and salt concentration. XRD analysis confirmed the predominantly amorphous nature of the optimized electrolyte. ATR-FTIR studies revealed the various functional groups associated with polymer nanocomposite electrolyte and demonstrated interactions among components through band shifts. Thermal analysis conducted through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) revealed a glass transition temperature of approximately 40.4 °C, with complete degradation occurring above 300 °C for the polymer electrolyte, comprising 7.5 wt% nanofillers and 12.5 wt% LiClO<sub>4</sub> salt. The optimized electrolyte exhibited the highest ionic conductivity of 0.129 mScm<sup>−1</sup>, an electrochemical stability window of 3.35 V, maximum cationic transference number of 0.70, DC conductivity of 7.94 μS/cm, tensile strength of 3.14 MPa and a maximum strain of 150 %. The structural and electrical relaxation time corresponds to the relaxation behavior of polymer and ions found to decreased to 0.50 μs and 0.03 μs respectively while coupling index drops to 15.55. The evaluation of interfacial resistance over a period of 10 days demonstrates the impact of moisture on interfacial resistance, wherein the resistance initially decreased and subsequently increased and stabilized. These results underscore the potential of this bio-based polymer nanocomposite electrolyte for energy storage applications.</div></div>","PeriodicalId":431,"journal":{"name":"Solid State Ionics","volume":"429 ","pages":"Article 116985"},"PeriodicalIF":3.3,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144750572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-07-31DOI: 10.1016/j.ssi.2025.116987
Sara Drvarič Talian , Nejc Urbanija , Miran Gaberšček
The impedance response of passivated lithium metal anodes has been the subject of numerous studies. However, the exact significance of the main contribution – the mid-frequency arc due to the formation of the solid electrolyte interphase (SEI) - has not been satisfactorily explained. In particular, many studies have pointed to the existence of two closely coupled arcs – instead of one, which further complicates the interpretation. This study systematically investigates the possible underlying processes that determine the impedance characteristics of the SEI using four electrolytes with concentrations ranging from 1 M to 10−4 M. The experimental results show that features attributed to processes in the electrolyte phase, such as migration and diffusion, scale significantly with concentration. However, the resistance associated with the coupled mid-frequency arc (the “SEI arc”) shows a modest increase, challenging conventional hypotheses. A novel two-dimensional transmission line model is introduced to account for the heterogeneous topology of the SEI and to capture the interplay of liquid and solid phases. The model accurately describes the observed trends over the entire concentration range and reveals the crucial influence of the SEI on the overall impedance. This work provides new insights into the structure-function relationships of the SEI and highlights the need for topology-aware modeling to understand lithium metal anodes.
{"title":"On the interpretation of the impedance response of a passivated lithium metal anode","authors":"Sara Drvarič Talian , Nejc Urbanija , Miran Gaberšček","doi":"10.1016/j.ssi.2025.116987","DOIUrl":"10.1016/j.ssi.2025.116987","url":null,"abstract":"<div><div>The impedance response of passivated lithium metal anodes has been the subject of numerous studies. However, the exact significance of the main contribution – the mid-frequency arc due to the formation of the solid electrolyte interphase (SEI) - has not been satisfactorily explained. In particular, many studies have pointed to the existence of two closely coupled arcs – instead of one, which further complicates the interpretation. This study systematically investigates the possible underlying processes that determine the impedance characteristics of the SEI using four electrolytes with concentrations ranging from 1 M to 10<sup>−4</sup> M. The experimental results show that features attributed to processes in the electrolyte phase, such as migration and diffusion, scale significantly with concentration. However, the resistance associated with the coupled mid-frequency arc (the “SEI arc”) shows a modest increase, challenging conventional hypotheses. A novel two-dimensional transmission line model is introduced to account for the heterogeneous topology of the SEI and to capture the interplay of liquid and solid phases. The model accurately describes the observed trends over the entire concentration range and reveals the crucial influence of the SEI on the overall impedance. This work provides new insights into the structure-function relationships of the SEI and highlights the need for topology-aware modeling to understand lithium metal anodes.</div></div>","PeriodicalId":431,"journal":{"name":"Solid State Ionics","volume":"429 ","pages":"Article 116987"},"PeriodicalIF":3.3,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144750452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Although all-solid-state batteries (ASSBs) have superior safety and higher energy density than conventional lithium-ion batteries (LIBs), concern regarding inadequate power density originate from the poor Li-ion conduction in composite electrode, especially at high C-rate. Tortuosity of solid electrolyte (SE) within the composite electrode has been considered as one of the major components which influence their electrochemical performance. However, research based on structural information for composite electrodes under actual pressure conditions is not sufficient. Here, we investigated the effect of solid electrolyte particle size on the voids and tortuosity of solid electrolyte in composite electrode and electrochemical performance of composite electrodes using in situ X-ray computed tomography. The results showed that fine Li3PS4 resulted in better packing and lowering tortuosity to increasing pressure compared to large Li3PS4, which enhanced the electrochemical performance, especially at higher pressure. A detailed analysis on shapes of voids revealed that plate-like voids with low elongation and flatness disappeared and more spherical voids with high elongation and flatness were emerged as external pressure increased. In addition, the voids in the composite electrode using fine Li3PS4 particles were less likely to interfere with Li-ion conduction pathways, which improved overall battery performance. This study highlights the important role of SE particle size in optimizing ASSB performance through improved microstructural properties.
{"title":"Investigating the impact of solid electrolyte particle size/void shape in modulating lithium-ion conduction pathways within graphite composite electrodes using in situ X-ray computed tomography","authors":"Yong Jun Park , Seunghoon Yang , Toshiki Watanabe , Kentaro Yamamoto , Atsushi Sakuda , Akitoshi Hayashi , Masahiro Tatsumisago , Mukesh Kumar , Neha Thakur , Toshiyuki Matsunaga , Yoshiharu Uchimoto","doi":"10.1016/j.ssi.2025.116975","DOIUrl":"10.1016/j.ssi.2025.116975","url":null,"abstract":"<div><div>Although all-solid-state batteries (ASSBs) have superior safety and higher energy density than conventional lithium-ion batteries (LIBs), concern regarding inadequate power density originate from the poor Li-ion conduction in composite electrode, especially at high C-rate. Tortuosity of solid electrolyte (SE) within the composite electrode has been considered as one of the major components which influence their electrochemical performance. However, research based on structural information for composite electrodes under actual pressure conditions is not sufficient. Here, we investigated the effect of solid electrolyte particle size on the voids and tortuosity of solid electrolyte in composite electrode and electrochemical performance of composite electrodes using in situ X-ray computed tomography. The results showed that fine Li<sub>3</sub>PS<sub>4</sub> resulted in better packing and lowering tortuosity to increasing pressure compared to large Li<sub>3</sub>PS<sub>4</sub>, which enhanced the electrochemical performance, especially at higher pressure. A detailed analysis on shapes of voids revealed that plate-like voids with low elongation and flatness disappeared and more spherical voids with high elongation and flatness were emerged as external pressure increased. In addition, the voids in the composite electrode using fine Li<sub>3</sub>PS<sub>4</sub> particles were less likely to interfere with Li-ion conduction pathways, which improved overall battery performance. This study highlights the important role of SE particle size in optimizing ASSB performance through improved microstructural properties.</div></div>","PeriodicalId":431,"journal":{"name":"Solid State Ionics","volume":"429 ","pages":"Article 116975"},"PeriodicalIF":3.3,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-07-29DOI: 10.1016/j.ssi.2025.116974
Robert A. Jackson , Peter Fielitz , Günter Borchardt
The calculated migration energies of the constituent elements of LaAlO3 are comparable to the corresponding calculated migration energies of LaGaO3 available in the literature. The resulting calculated ranking of the migration energies, , is valid for various nominally undoped oxide perovskites (ABO3). From this ranking it must be concluded that for a specific temperature the ranking of the self-diffusivities of the constituent elements in nominally undoped oxide perovskites reads . The low cation mobilities in undoped oxide perovskites hamper the experimental determination of the diffusivities of the cations considerably. That is predominantly true for the B site elements which probably migrate via an antisite mechanism in the A sublattice. This conjecture is rationalized by an appropriate mechanistic model which is principally valid for any ternary oxide system with very different defect concentrations and cation mobilities in the two cation sublattices.
{"title":"Migration energies of the constituent ions in LaAlO3","authors":"Robert A. Jackson , Peter Fielitz , Günter Borchardt","doi":"10.1016/j.ssi.2025.116974","DOIUrl":"10.1016/j.ssi.2025.116974","url":null,"abstract":"<div><div>The calculated migration energies of the constituent elements of LaAlO<sub>3</sub> are comparable to the corresponding calculated migration energies of LaGaO<sub>3</sub> available in the literature. The resulting calculated ranking of the migration energies, <span><math><mi>Δ</mi><msubsup><mi>E</mi><mi>m</mi><mtext>Oxygen</mtext></msubsup><mo><</mo><mi>Δ</mi><msubsup><mi>E</mi><mi>m</mi><mtext>A site cation</mtext></msubsup><mo><</mo><mi>Δ</mi><msubsup><mi>E</mi><mi>m</mi><mtext>B site cation</mtext></msubsup></math></span>, is valid for various nominally undoped oxide perovskites (ABO<sub>3</sub>). From this ranking it must be concluded that for a specific temperature the ranking of the self-diffusivities of the constituent elements in nominally undoped oxide perovskites reads <span><math><msub><mi>D</mi><mtext>Oxygen</mtext></msub><mo>≫</mo><msub><mi>D</mi><mtext>A site cation</mtext></msub><mo>≫</mo><msub><mi>D</mi><mtext>B site cation</mtext></msub></math></span>. The low cation mobilities in undoped oxide perovskites hamper the experimental determination of the diffusivities of the cations considerably. That is predominantly true for the B site elements which probably migrate via an antisite mechanism in the A sublattice. This conjecture is rationalized by an appropriate mechanistic model which is principally valid for any ternary oxide system with very different defect concentrations and cation mobilities in the two cation sublattices.</div></div>","PeriodicalId":431,"journal":{"name":"Solid State Ionics","volume":"429 ","pages":"Article 116974"},"PeriodicalIF":3.3,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-07-29DOI: 10.1016/j.ssi.2025.116986
Bin Li , Wenlin Gong , Mingyao Yang , Si Lin , Yan Liu , Jiayi Su , Jie Zhang , Guocong Liu
The practical application of fast-charging lithium-ion batteries is hindered by interfacial instability at graphite anodes, primarily due to uncontrolled electrolyte decomposition and the formation of resistive solid electrolyte interphase (SEI) layers. Herein, we report ethyl difluoroacetate (EDFA) as a fluorinated additive for conventional LiPF₆/EC-EMC electrolytes to address these challenges. Electrochemical measurements demonstrate that EDFA undergoes preferential reduction to form a stable, fluorine-rich SEI, which enhances interfacial stability and facilitates Li+ transport. As a result, graphite/Li half-cells with EDFA exhibit significantly improved performance, with capacity retention increasing from 81.8 % to 93.4 % after 100 cycles and 3C-rate capacity rising from 49.1 to 99.5 mAh·g−1. SEM, TEM, and XPS analyses confirm the formation of a uniform, compact and fluorine-rich SEI that mitigates parasitic reactions and reduces impedance. This work provides a viable strategy to enhance fast-charging performance in commercial battery systems through additive engineering.
{"title":"Ethyl difluoroacetate additive engineering for fast-charging and durable graphite anodes in lithium-ion batteries","authors":"Bin Li , Wenlin Gong , Mingyao Yang , Si Lin , Yan Liu , Jiayi Su , Jie Zhang , Guocong Liu","doi":"10.1016/j.ssi.2025.116986","DOIUrl":"10.1016/j.ssi.2025.116986","url":null,"abstract":"<div><div>The practical application of fast-charging lithium-ion batteries is hindered by interfacial instability at graphite anodes, primarily due to uncontrolled electrolyte decomposition and the formation of resistive solid electrolyte interphase (SEI) layers. Herein, we report ethyl difluoroacetate (EDFA) as a fluorinated additive for conventional LiPF₆/EC-EMC electrolytes to address these challenges. Electrochemical measurements demonstrate that EDFA undergoes preferential reduction to form a stable, fluorine-rich SEI, which enhances interfacial stability and facilitates Li<sup>+</sup> transport. As a result, graphite/Li half-cells with EDFA exhibit significantly improved performance, with capacity retention increasing from 81.8 % to 93.4 % after 100 cycles and 3C-rate capacity rising from 49.1 to 99.5 mAh·g<sup>−1</sup>. SEM, TEM, and XPS analyses confirm the formation of a uniform, compact and fluorine-rich SEI that mitigates parasitic reactions and reduces impedance. This work provides a viable strategy to enhance fast-charging performance in commercial battery systems through additive engineering.</div></div>","PeriodicalId":431,"journal":{"name":"Solid State Ionics","volume":"429 ","pages":"Article 116986"},"PeriodicalIF":3.3,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-07-26DOI: 10.1016/j.ssi.2025.116973
Tatsuya Kawada
<div><div>Oxygen exchange kinetics was investigated to model the current-potential relationship of mixed conducting oxide electrodes used in SOFC and SOEC. Focusing on La<sub>0.6</sub>Sr<sub>0.4</sub>CoO<sub>3</sub> as a model material, experimental evidence so far obtained in our group were summarized and reanalyzed. The reaction order analysis suggested a complex reaction mechanism, for which we came to think of two series kinetics, surface process and subsurface process. The former refers to an exchange process between gas-phase oxygen molecules and some sort of surface oxygen species. The latter refers to the exchange of surface oxygen with bulk oxide ions, and the reaction barrier is not necessarily oxygen transport, but may be electron transport/transfer for oxygen in/ex-corporation This hypothesis appeared to resolve some of our remaining questions regarding the experimental results, such as scattered <em>p</em><sub>O<sub>2</sub></sub> dependence in high partial pressure range, the higher isotope exchange rates than electrochemical impedance, and the reaction rate enhancement in the presence of the LaSrCoO<sub>4</sub> phase. While a single piece of such experimental evidence is insufficient to prove the hypothesis, considering all the results together provides strong support. We then tried to separate the contributions of surface and subsurface processes by measuring the surface oxygen potential using a porous oxygen sensor. It revealed that the surface process is written as <span><math><msub><mi>J</mi><mi>s</mi></msub><mo>=</mo><msub><mi>J</mi><mrow><mi>s</mi><mo>,</mo><mn>0</mn></mrow></msub><mo>∙</mo><mi>δ</mi><mo>∙</mo><mfenced><mrow><msubsup><mi>a</mi><mrow><mi>O</mi><mo>,</mo><mi>s</mi></mrow><mn>2</mn></msubsup><mo>−</mo><msub><mi>p</mi><mrow><msub><mi>O</mi><mn>2</mn></msub><mo>,</mo><mi>g</mi></mrow></msub></mrow></mfenced></math></span> and the subsurface process as <span><math><msub><mi>J</mi><mi>ss</mi></msub><mo>=</mo><msub><mi>J</mi><mrow><mi>ss</mi><mo>,</mo><mn>0</mn></mrow></msub><mo>∙</mo><mfenced><mrow><msub><mi>a</mi><mrow><mi>O</mi><mo>,</mo><mi>e</mi></mrow></msub><msubsup><mi>a</mi><mrow><mi>O</mi><mo>,</mo><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup><mo>−</mo><msubsup><mi>a</mi><mrow><mi>O</mi><mo>,</mo><mi>e</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup><msub><mi>a</mi><mrow><mi>O</mi><mo>,</mo><mi>s</mi></mrow></msub></mrow></mfenced><mo>=</mo><msub><mi>J</mi><mrow><mi>ss</mi><mo>,</mo><mn>0</mn></mrow></msub><mfenced><mrow><mi>exp</mi><mfenced><mfrac><mrow><mi>β</mi><mo>∆</mo><msub><mi>μ</mi><msub><mi>O</mi><mn>2</mn></msub></msub></mrow><mi>RT</mi></mfrac></mfenced><mo>−</mo><mi>exp</mi><mfenced><mrow><mo>−</mo><mfrac><mrow><mfenced><mrow><mn>1</mn><mo>−</mo><mi>β</mi></mrow></mfenced><mo>∆</mo><msub><mi>μ</mi><msub><mi>O</mi><mn>2</mn></msub></msub></mrow><mi>RT</mi></mfrac></mrow></mfenced></mrow></mfenced></math></span>, which are in good agreement with the experimental data even for f
{"title":"High temperature oxygen exchange reaction on dense and porous La0.6Sr0.4CoO3-δ electrodes: An overview of the experimental evidence for modeling","authors":"Tatsuya Kawada","doi":"10.1016/j.ssi.2025.116973","DOIUrl":"10.1016/j.ssi.2025.116973","url":null,"abstract":"<div><div>Oxygen exchange kinetics was investigated to model the current-potential relationship of mixed conducting oxide electrodes used in SOFC and SOEC. Focusing on La<sub>0.6</sub>Sr<sub>0.4</sub>CoO<sub>3</sub> as a model material, experimental evidence so far obtained in our group were summarized and reanalyzed. The reaction order analysis suggested a complex reaction mechanism, for which we came to think of two series kinetics, surface process and subsurface process. The former refers to an exchange process between gas-phase oxygen molecules and some sort of surface oxygen species. The latter refers to the exchange of surface oxygen with bulk oxide ions, and the reaction barrier is not necessarily oxygen transport, but may be electron transport/transfer for oxygen in/ex-corporation This hypothesis appeared to resolve some of our remaining questions regarding the experimental results, such as scattered <em>p</em><sub>O<sub>2</sub></sub> dependence in high partial pressure range, the higher isotope exchange rates than electrochemical impedance, and the reaction rate enhancement in the presence of the LaSrCoO<sub>4</sub> phase. While a single piece of such experimental evidence is insufficient to prove the hypothesis, considering all the results together provides strong support. We then tried to separate the contributions of surface and subsurface processes by measuring the surface oxygen potential using a porous oxygen sensor. It revealed that the surface process is written as <span><math><msub><mi>J</mi><mi>s</mi></msub><mo>=</mo><msub><mi>J</mi><mrow><mi>s</mi><mo>,</mo><mn>0</mn></mrow></msub><mo>∙</mo><mi>δ</mi><mo>∙</mo><mfenced><mrow><msubsup><mi>a</mi><mrow><mi>O</mi><mo>,</mo><mi>s</mi></mrow><mn>2</mn></msubsup><mo>−</mo><msub><mi>p</mi><mrow><msub><mi>O</mi><mn>2</mn></msub><mo>,</mo><mi>g</mi></mrow></msub></mrow></mfenced></math></span> and the subsurface process as <span><math><msub><mi>J</mi><mi>ss</mi></msub><mo>=</mo><msub><mi>J</mi><mrow><mi>ss</mi><mo>,</mo><mn>0</mn></mrow></msub><mo>∙</mo><mfenced><mrow><msub><mi>a</mi><mrow><mi>O</mi><mo>,</mo><mi>e</mi></mrow></msub><msubsup><mi>a</mi><mrow><mi>O</mi><mo>,</mo><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup><mo>−</mo><msubsup><mi>a</mi><mrow><mi>O</mi><mo>,</mo><mi>e</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup><msub><mi>a</mi><mrow><mi>O</mi><mo>,</mo><mi>s</mi></mrow></msub></mrow></mfenced><mo>=</mo><msub><mi>J</mi><mrow><mi>ss</mi><mo>,</mo><mn>0</mn></mrow></msub><mfenced><mrow><mi>exp</mi><mfenced><mfrac><mrow><mi>β</mi><mo>∆</mo><msub><mi>μ</mi><msub><mi>O</mi><mn>2</mn></msub></msub></mrow><mi>RT</mi></mfrac></mfenced><mo>−</mo><mi>exp</mi><mfenced><mrow><mo>−</mo><mfrac><mrow><mfenced><mrow><mn>1</mn><mo>−</mo><mi>β</mi></mrow></mfenced><mo>∆</mo><msub><mi>μ</mi><msub><mi>O</mi><mn>2</mn></msub></msub></mrow><mi>RT</mi></mfrac></mrow></mfenced></mrow></mfenced></math></span>, which are in good agreement with the experimental data even for f","PeriodicalId":431,"journal":{"name":"Solid State Ionics","volume":"429 ","pages":"Article 116973"},"PeriodicalIF":3.0,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-07-25DOI: 10.1016/j.ssi.2025.116972
Paul Nizet , Francesco Chiabrera , Alex Morata , Albert Tarancón
Electrochemical Impedance Spectroscopy (EIS) is the conventional technique for studying the electrical response of individual materials or complete energy devices such as batteries, fuel cells, and supercapacitors. However, EIS has several limitations, including its spatial resolution, the description of ion insertion phenomena (especially when multiple ion species are involved), and the presence of porous electrodes. In this paper, Generalized Ionic Impedance Spectroscopy (GIIS) is proposed to address these issues by complementing traditional EIS to analyze ionic concentration changes under an AC voltage stimulus. A broad range of characterization techniques can be employed to analyze such ionic concentration variations, as these significantly modify the functional properties of the material, such as optical, magnetic, and electrical behavior. Some of these techniques also offer high spatial resolution, enabling lateral and depth profiling analysis. This study provides a theoretical framework for the development of GIIS in the field of energy, analyzing battery-like and fuel cell-like devices while resolving the major limitations of EIS mentioned above. The proven versatility of GIIS opens new pathways for the detailed characterization of energy materials and devices, advancing the understanding of low-frequency fundamental electrochemical processes and broadening the scope of their applications. While many of the discussed cases are experimentally validated, others are presented as perspectives of GIIS applications.
{"title":"When ions are in charge: Generalized ionic impedance spectroscopy for characterizing energy materials and devices","authors":"Paul Nizet , Francesco Chiabrera , Alex Morata , Albert Tarancón","doi":"10.1016/j.ssi.2025.116972","DOIUrl":"10.1016/j.ssi.2025.116972","url":null,"abstract":"<div><div>Electrochemical Impedance Spectroscopy (EIS) is the conventional technique for studying the electrical response of individual materials or complete energy devices such as batteries, fuel cells, and supercapacitors. However, EIS has several limitations, including its spatial resolution, the description of ion insertion phenomena (especially when multiple ion species are involved), and the presence of porous electrodes. In this paper, Generalized Ionic Impedance Spectroscopy (GIIS) is proposed to address these issues by complementing traditional EIS to analyze ionic concentration changes under an AC voltage stimulus. A broad range of characterization techniques can be employed to analyze such ionic concentration variations, as these significantly modify the functional properties of the material, such as optical, magnetic, and electrical behavior. Some of these techniques also offer high spatial resolution, enabling lateral and depth profiling analysis. This study provides a theoretical framework for the development of GIIS in the field of energy, analyzing battery-like and fuel cell-like devices while resolving the major limitations of EIS mentioned above. The proven versatility of GIIS opens new pathways for the detailed characterization of energy materials and devices, advancing the understanding of low-frequency fundamental electrochemical processes and broadening the scope of their applications. While many of the discussed cases are experimentally validated, others are presented as perspectives of GIIS applications.</div></div>","PeriodicalId":431,"journal":{"name":"Solid State Ionics","volume":"429 ","pages":"Article 116972"},"PeriodicalIF":3.0,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144702473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-07-25DOI: 10.1016/j.ssi.2025.116976
Akanksha Yadav , Yeting Wen , Xi Yang , Dunji Yu , Yan Chen , Kevin Huang
Solid oxide ion electrolytes (SOEs) play a crucial role in determining the operating temperature, cost, and lifetime of solid oxide electrochemical devices. The most competitive SOEs are typically found in cubic-structured fluorides (e.g., ZrO2-based and CeO2-based) and perovskites (e.g., LaGaO3-based and Ba(Zr,Ce)O3-based). However, the discovery of new high-conductivity SOE systems has been very limited in the history of solid state ionics. Here, we explore a new cubic-structured perovskite, Ba1-xNaxZr1-xGaxO3-x (BNZG), as a potential oxide-ion conductor. Compared to La0.8Sr0.2Ga0.8Mg0.2O2.8 (LSGM), a state-of-the-art perovskite electrolyte, BNZG exhibits a comparable bulk ionic conductivity (∼0.01 S/cm at 600°C) while reducing Ga content by 40 %. Additionally, compared to BaZr0.8Y0.2O2.9 (BZY), another widely studied perovskite electrolyte, BNZG shows excellent sinterability at lower temperatures. Ab Initio molecular dynamics (AIMD) simulations suggest that BNZG is an oxide-ion conductor, particularly at higher temperatures, which is also confirmed by high oxide-ion transport number (>0.99) and conductivity independent of oxygen and water vapor partial pressures. Furthermore, BNZG is stable in CO2/air and compatible with active perovskite cathodes such as La1-xSrxCoO3-δ without the use of barrier layer. We also show that the high grain-boundary resistance originated from Ga segregation could be one critical issue for BNZG application in intermediate temperature solid oxide cells.
{"title":"High Oxide-ion Conductivity in Cubic Perovskite Na- and Ga-doped BaZrO3","authors":"Akanksha Yadav , Yeting Wen , Xi Yang , Dunji Yu , Yan Chen , Kevin Huang","doi":"10.1016/j.ssi.2025.116976","DOIUrl":"10.1016/j.ssi.2025.116976","url":null,"abstract":"<div><div>Solid oxide ion electrolytes (SOEs) play a crucial role in determining the operating temperature, cost, and lifetime of solid oxide electrochemical devices. The most competitive SOEs are typically found in cubic-structured fluorides (e.g., ZrO<sub>2</sub>-based and CeO<sub>2</sub>-based) and perovskites (e.g., LaGaO<sub>3</sub>-based and Ba(<em>Zr</em>,<em>Ce</em>)O<sub>3</sub>-based). However, the discovery of new high-conductivity SOE systems has been very limited in the history of solid state ionics. Here, we explore a new cubic-structured perovskite, Ba<sub>1-x</sub>Na<sub>x</sub>Zr<sub>1-x</sub>Ga<sub>x</sub>O<sub>3-x</sub> (BNZG), as a potential oxide-ion conductor. Compared to La<sub>0.8</sub>Sr<sub>0.2</sub>Ga<sub>0.8</sub>Mg<sub>0.2</sub>O<sub>2.8</sub> (LSGM), a state-of-the-art perovskite electrolyte, BNZG exhibits a comparable bulk ionic conductivity (∼0.01 S/cm at 600°C) while reducing Ga content by 40 %. Additionally, compared to BaZr<sub>0.8</sub>Y<sub>0.2</sub>O<sub>2.9</sub> (BZY), another widely studied perovskite electrolyte, BNZG shows excellent sinterability at lower temperatures. Ab Initio molecular dynamics (AIMD) simulations suggest that BNZG is an oxide-ion conductor, particularly at higher temperatures, which is also confirmed by high oxide-ion transport number (>0.99) and conductivity independent of oxygen and water vapor partial pressures. Furthermore, BNZG is stable in CO<sub>2</sub>/air and compatible with active perovskite cathodes such as La<sub>1-x</sub>Sr<sub>x</sub>CoO<sub>3-δ</sub> without the use of barrier layer. We also show that the high grain-boundary resistance originated from Ga segregation could be one critical issue for BNZG application in intermediate temperature solid oxide cells.</div></div>","PeriodicalId":431,"journal":{"name":"Solid State Ionics","volume":"429 ","pages":"Article 116976"},"PeriodicalIF":3.0,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144702474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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