Pub Date : 2025-12-19DOI: 10.1016/j.solidstatesciences.2025.108187
Valentin Yu. Irkhin , Zhehong Liu , Danil A. Myakotnikov , Evgenia V. Komleva , Youwen Long , Sergey V. Streltsov
Experimental data on the specific heat of quadruple perovskites ACuFeReO12 (A = Mn, Cu, La, Ce, Dy) are presented, demonstrating an anomalous concave-down vs. curve and a bell-shaped feature in plotted against on a logarithmic scale. This feature is most pronounced for A = Cu and Mn. These findings can be explained by the rattling phenomenon, previously identified in other systems such as filled skutterudites and -pyrochlores. Using first-principles DFT+U calculations, the presence of a rattling mode in A= Mn is directly confirmed. A qualitative interpretation of the rattling mechanism in terms of a pseudo-Jahn–Teller effect is proposed.
{"title":"Anomalous lattice specific heat and rattling phonon modes in quadruple perovskites","authors":"Valentin Yu. Irkhin , Zhehong Liu , Danil A. Myakotnikov , Evgenia V. Komleva , Youwen Long , Sergey V. Streltsov","doi":"10.1016/j.solidstatesciences.2025.108187","DOIUrl":"10.1016/j.solidstatesciences.2025.108187","url":null,"abstract":"<div><div>Experimental data on the specific heat <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> of quadruple perovskites <em>A</em>Cu<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>Fe<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Re<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O<sub>12</sub> (<em>A</em> = Mn, Cu, La, Ce, Dy) are presented, demonstrating an anomalous concave-down <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mi>p</mi></mrow></msub><mo>/</mo><mi>T</mi></mrow></math></span> vs. <span><math><msup><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> curve and a bell-shaped feature in <span><math><mrow><mi>β</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><mrow><mo>(</mo><msub><mrow><mi>C</mi></mrow><mrow><mi>p</mi></mrow></msub><mo>−</mo><mi>γ</mi><mi>T</mi><mo>)</mo></mrow><mo>/</mo><msup><mrow><mi>T</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></math></span> plotted against <span><math><mi>T</mi></math></span> on a logarithmic scale. This feature is most pronounced for <em>A</em> = Cu and Mn. These findings can be explained by the rattling phenomenon, previously identified in other systems such as filled skutterudites and <span><math><mi>β</mi></math></span>-pyrochlores. Using first-principles DFT+U calculations, the presence of a rattling mode in <em>A</em>= Mn is directly confirmed. A qualitative interpretation of the rattling mechanism in terms of a pseudo-Jahn–Teller effect is proposed.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"173 ","pages":"Article 108187"},"PeriodicalIF":3.3,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The CuO-ZnO/3-dimensional phosphorus and nitrogen co-doped reduced graphene oxide (CZ/3DNPG) nanocomposite was successfully synthesized via a one-step hydrothermal method and evaluated as a high-performance electrode material for supercapacitor applications. The microstructural and structural characteristics, as well as the electrochemical properties of the nanocomposite, were thoroughly investigated. Doping, compositing, and 3D structure were employed to enhance pore density, surface area, and pore volume, thereby providing abundant expedient electroactive sites and facilitating efficient electron/ion transfer, ultimately improving overall electrochemical processes. CZ/3DNPG achieved a high specific capacitance of 714 F g−1 at 1 A g−1 within a voltage window of −0.6 to 0.6 V (vs. Ag/AgCl) in a three-electrode system using 6 M KOH as the electrolyte. In the two-electrode configuration, the material exhibited a specific capacitance of 119 F g−1, an energy density of 65.5 Wh kg−1, and a power density of 1700 W kg−1 at 1 A g−1 in 1 M TEMA-BF4 dissolved in propylene carbonate. Notably, cycling in a symmetrical two-electrode system showed an increasing capacitance trend, with 160 % capacity retention after 24,000 cycles. These qualities, which improve structural durability, increase ion transport efficiency, and facilitate redox processes, are attributed to the synergistic effect of the metal oxides and the heteroatom-doped porous graphene matrix. This study demonstrates that CZ/3DNPG is an advanced material for modern energy storage systems.
通过一步水热法成功合成了CuO-ZnO/三维磷氮共掺杂还原氧化石墨烯（CZ/3DNPG）纳米复合材料，并被评价为一种用于超级电容器的高性能电极材料。研究了纳米复合材料的微观组织、结构特征以及电化学性能。通过掺杂、复合和三维结构来增强孔密度、比表面积和孔体积，从而提供丰富的有利电活性位点，促进有效的电子/离子转移，最终改善整个电化学过程。CZ/3DNPG在- 0.6 ~ 0.6 V （vs. Ag/AgCl）电压窗下，以6 M KOH作为电解液，在1 ag−1电压下获得了714 F g−1的高比电容。在双电极结构下，材料的比电容为119 F g−1，能量密度为65.5 Wh kg−1，在溶解于碳酸丙烯酯中的1 M TEMA-BF4中，在1 a g−1条件下的功率密度为1700 W kg−1。值得注意的是，在对称双电极系统中循环显示出电容增加的趋势，24000次循环后容量保持率为160%。这些改善结构耐久性、提高离子传输效率和促进氧化还原过程的品质归功于金属氧化物和杂原子掺杂多孔石墨烯基体的协同效应。该研究表明，CZ/3DNPG是现代储能系统的先进材料。
{"title":"Synthesis of CuO-ZnO/N, P-doped 3D rGO hybrid supercapacitive electrode: Fabrication and electrochemical characterization","authors":"Neda Nazari , Sajad Mirzaee , Adrine Malek Khachatourian , Mohammad Golmohammad , Arash Javanmard , Rasoul Sarraf-Mamoory , Rene Zahrhuber , Christoph Unterweger","doi":"10.1016/j.solidstatesciences.2025.108186","DOIUrl":"10.1016/j.solidstatesciences.2025.108186","url":null,"abstract":"<div><div>The CuO-ZnO/3-dimensional phosphorus and nitrogen co-doped reduced graphene oxide (CZ/3DNPG) nanocomposite was successfully synthesized via a one-step hydrothermal method and evaluated as a high-performance electrode material for supercapacitor applications. The microstructural and structural characteristics, as well as the electrochemical properties of the nanocomposite, were thoroughly investigated. Doping, compositing, and 3D structure were employed to enhance pore density, surface area, and pore volume, thereby providing abundant expedient electroactive sites and facilitating efficient electron/ion transfer, ultimately improving overall electrochemical processes. CZ/3DNPG achieved a high specific capacitance of 714 F g<sup>−1</sup> at 1 A g<sup>−1</sup> within a voltage window of −0.6 to 0.6 V (vs. Ag/AgCl) in a three-electrode system using 6 M KOH as the electrolyte. In the two-electrode configuration, the material exhibited a specific capacitance of 119 F g<sup>−1</sup>, an energy density of 65.5 Wh kg<sup>−1</sup>, and a power density of 1700 W kg<sup>−1</sup> at 1 A g<sup>−1</sup> in 1 M TEMA-BF<sub>4</sub> dissolved in propylene carbonate. Notably, cycling in a symmetrical two-electrode system showed an increasing capacitance trend, with 160 % capacity retention after 24,000 cycles. These qualities, which improve structural durability, increase ion transport efficiency, and facilitate redox processes, are attributed to the synergistic effect of the metal oxides and the heteroatom-doped porous graphene matrix. This study demonstrates that CZ/3DNPG is an advanced material for modern energy storage systems.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"173 ","pages":"Article 108186"},"PeriodicalIF":3.3,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.solidstatesciences.2025.108184
Khalid A. Alzahrani , Sonu , Vatika Soni , Pankaj Raizada , Aftab Aslam Parwaz Khan , Naved Azum , Muhammad Nadeem Arshad , Pardeep Singh
The increasing global demand for drinkable water, intensified by human-induced environmental degradation, immediately calls for sustainable and advanced solutions to safeguard vital water resources. This research effectively improved the photodegradation of Cefixime by developing a new and efficient Ag2S/BiVO4/AgI nanocomposite utilizing a basic co-precipitation synthesis approach. The crystal size of Ag2S/BiVO4/AgI photocatalyst is around 16.20 nm, signifying strong interparticle bonding as confirmed from XRD spectra. The dual S-scheme heterojunction formed among BiVO4, AgI, and Ag2S enabled effective interfacial charge migration, significantly improving charge-carrier concentration, isolation, and migration, as confirmed by optoelectronic as well as electrochemical studies. Improved band alignment and light absorption across the visible range contributed to the superior photocatalytic response. Further, scavenger experiments revealed that •O2− and •OH radicals as the dominant reactive species governing the photodegradation reaction. Consequently, the Ag2S/BiVO4/AgI nanocomposite attained an outstanding cefixime degradation efficacy of 95.31 %, and recyclability for five cycles depicting its remarkable photocatalytic potential as well as stability respectively. This research provides valuable understanding into designing multi-component S-scheme nanocomposite for next-generation environmental remediation technologies.
{"title":"Unveiling potential of dual S-scheme derived Ag2S/BiVO4/AgI for cefixime photocatalytic degradation","authors":"Khalid A. Alzahrani , Sonu , Vatika Soni , Pankaj Raizada , Aftab Aslam Parwaz Khan , Naved Azum , Muhammad Nadeem Arshad , Pardeep Singh","doi":"10.1016/j.solidstatesciences.2025.108184","DOIUrl":"10.1016/j.solidstatesciences.2025.108184","url":null,"abstract":"<div><div>The increasing global demand for drinkable water, intensified by human-induced environmental degradation, immediately calls for sustainable and advanced solutions to safeguard vital water resources. This research effectively improved the photodegradation of Cefixime by developing a new and efficient Ag<sub>2</sub>S/BiVO<sub>4</sub>/AgI nanocomposite utilizing a basic co-precipitation synthesis approach. The crystal size of Ag<sub>2</sub>S/BiVO<sub>4</sub>/AgI photocatalyst is around 16.20 nm, signifying strong interparticle bonding as confirmed from XRD spectra. The dual S-scheme heterojunction formed among BiVO<sub>4</sub>, AgI, and Ag<sub>2</sub>S enabled effective interfacial charge migration, significantly improving charge-carrier concentration, isolation, and migration, as confirmed by optoelectronic as well as electrochemical studies. Improved band alignment and light absorption across the visible range contributed to the superior photocatalytic response. Further, scavenger experiments revealed that •O<sub>2</sub><sup>−</sup> and •OH radicals as the dominant reactive species governing the photodegradation reaction. Consequently, the Ag<sub>2</sub>S/BiVO<sub>4</sub>/AgI nanocomposite attained an outstanding cefixime degradation efficacy of 95.31 %, and recyclability for five cycles depicting its remarkable photocatalytic potential as well as stability respectively. This research provides valuable understanding into designing multi-component S-scheme nanocomposite for next-generation environmental remediation technologies.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"173 ","pages":"Article 108184"},"PeriodicalIF":3.3,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-15DOI: 10.1016/j.solidstatesciences.2025.108182
K. Nepal , A. Gautam , R. Hussein , K. Konstantinou , S.R. Elliott , C. Ugwumadu , D.A. Drabold
We report new insights into the electronic, structural, and transport (heat and charge) properties of the phase-change memory material amorphous GeSbTe. Using realistic structural models of Konstantinou et al., (2019), we analyze the topology, electronic states, and lattice dynamics with density functional methods, including hybrid-functional calculations and machine-learned interatomic potentials. The Kohn–Sham orbitals near the Fermi level display a strong electron–phonon coupling, and exhibit large energy fluctuations at room temperature. The conduction tail states exhibit larger phonon-induced fluctuations than the valence tail states. To resolve transport at the atomic scale, we employ space-projected electronic conductivity and site-projected thermal conductivity methods. Local analysis of heat transport highlights the role of filamentary networks dominated by Te, with Sb and Ge making progressively smaller contributions.
{"title":"Electronic and thermal properties of the phase-change memory material, Ge2Sb2Te5, and results from spatially resolved transport calculations","authors":"K. Nepal , A. Gautam , R. Hussein , K. Konstantinou , S.R. Elliott , C. Ugwumadu , D.A. Drabold","doi":"10.1016/j.solidstatesciences.2025.108182","DOIUrl":"10.1016/j.solidstatesciences.2025.108182","url":null,"abstract":"<div><div>We report new insights into the electronic, structural, and transport (heat and charge) properties of the phase-change memory material amorphous Ge<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Sb<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Te<span><math><msub><mrow></mrow><mrow><mn>5</mn></mrow></msub></math></span>. Using realistic structural models of Konstantinou et al., (2019), we analyze the topology, electronic states, and lattice dynamics with density functional methods, including hybrid-functional calculations and machine-learned interatomic potentials. The Kohn–Sham orbitals near the Fermi level display a strong electron–phonon coupling, and exhibit large energy fluctuations at room temperature. The conduction tail states exhibit larger phonon-induced fluctuations than the valence tail states. To resolve transport at the atomic scale, we employ space-projected electronic conductivity and site-projected thermal conductivity methods. Local analysis of heat transport highlights the role of filamentary networks dominated by Te, with Sb and Ge making progressively smaller contributions.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"173 ","pages":"Article 108182"},"PeriodicalIF":3.3,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Al86Ni4Co4Nd6 and Al86Ni6Co2Nd6 amorphous ribbons were obtained by melt spinning and their crystallization kinetics was investigated using differential scanning calorimetry (DSC) and fast scanning calorimetry (FSC) methods. It is shown that transition from amorphous to crystalline state goes through several stages depending on Ni/Co ratio. The increase in nickel content leads to a significant change in crystallization path. Avrami exponent coefficient and some other parameters for amorphous/crystalline Al-Ni-Co-Nd alloys were determined using Kolmogorov-Jones-Mehl-Avrami (KJMA) model in the variant for non-isothermal crystallization.
{"title":"Investigation of non-isothermal crystallization in Al-Ni-Co-Nd amorphous alloys by slow and fast scanning calorimetry","authors":"B.A. Rusanov , T.A. Mukhametzyanov , V.E. Sidorov , S.A. Petrova , A.A. Notfullin","doi":"10.1016/j.solidstatesciences.2025.108179","DOIUrl":"10.1016/j.solidstatesciences.2025.108179","url":null,"abstract":"<div><div>Al<sub>86</sub>Ni<sub>4</sub>Co<sub>4</sub>Nd<sub>6</sub> and Al<sub>86</sub>Ni<sub>6</sub>Co<sub>2</sub>Nd<sub>6</sub> amorphous ribbons were obtained by melt spinning and their crystallization kinetics was investigated using differential scanning calorimetry (DSC) and fast scanning calorimetry (FSC) methods. It is shown that transition from amorphous to crystalline state goes through several stages depending on Ni/Co ratio. The increase in nickel content leads to a significant change in crystallization path. Avrami exponent coefficient and some other parameters for amorphous/crystalline Al-Ni-Co-Nd alloys were determined using Kolmogorov-Jones-Mehl-Avrami (KJMA) model in the variant for non-isothermal crystallization.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"173 ","pages":"Article 108179"},"PeriodicalIF":3.3,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.solidstatesciences.2025.108183
L.L. Bao , H. Yibole , S. Erdmann , H.İ. Sözen , T. Klüner , F. Guillou
Compounds crystallizing in the Fe2P-type hexagonal structure are attracting interest as functional magnetic materials, including for the giant magnetocaloric effect displayed by Mn-rich (Mn,Fe)2(P,Ge) quaternary compounds. In this work, we systematically investigate the structural and magnetic phase diagrams of ternary compounds Fe∼2P1-xGex (0 ≤ x ≤ 1.0) through both theoretical calculations and experiments, aiming to isolate and clarifying the consequences of Ge for P metalloid substitutions. Ge can substitute P within the hexagonal Fe2P-type structure up to x ≈ 0.175. Beyond this limit, the hexagonal Fe5Ge3 phase forms, limiting the Ge content entering the Fe2P phase and thereby defining the solubility limit. The appearance of secondary phases is associated with a predicted reduced formation energy of the Fe2P-phase upon Ge substitutions. Theoretical calculations indicate that Ge for P substitution stabilizes a higher moment on Fe at the 3f site, leading to an increase in saturation magnetization, which is experimentally confirmed. Within the solubility range, the Curie temperature increases sharply up to ∼550 K as the Ge content rises, while simultaneously inducing a magnetocrystalline anisotropy at room temperature. Powder X-ray diffraction on oriented samples indicates that Fe1.95P1-xGex (0 ≤ x ≤ 0.1) exhibits a c-axis easy magnetic axis.
{"title":"Phase formation, structure and magnetic properties of Ge substituted Fe2P compounds","authors":"L.L. Bao , H. Yibole , S. Erdmann , H.İ. Sözen , T. Klüner , F. Guillou","doi":"10.1016/j.solidstatesciences.2025.108183","DOIUrl":"10.1016/j.solidstatesciences.2025.108183","url":null,"abstract":"<div><div>Compounds crystallizing in the Fe<sub>2</sub>P-type hexagonal structure are attracting interest as functional magnetic materials, including for the giant magnetocaloric effect displayed by Mn-rich (Mn,Fe)<sub>2</sub>(P,Ge) quaternary compounds. In this work, we systematically investigate the structural and magnetic phase diagrams of <em>ternary</em> compounds Fe<sub>∼2</sub>P<sub>1-<em>x</em></sub>Ge<sub><em>x</em></sub> (0 ≤ <em>x</em> ≤ 1.0) through both theoretical calculations and experiments, aiming to isolate and clarifying the consequences of Ge for P metalloid substitutions. Ge can substitute P within the hexagonal Fe<sub>2</sub>P-type structure up to <em>x</em> ≈ 0.175. Beyond this limit, the hexagonal Fe<sub>5</sub>Ge<sub>3</sub> phase forms, limiting the Ge content entering the Fe<sub>2</sub>P phase and thereby defining the solubility limit. The appearance of secondary phases is associated with a predicted reduced formation energy of the Fe<sub>2</sub>P-phase upon Ge substitutions. Theoretical calculations indicate that Ge for P substitution stabilizes a higher moment on Fe at the 3<em>f</em> site, leading to an increase in saturation magnetization, which is experimentally confirmed. Within the solubility range, the Curie temperature increases sharply up to ∼550 K as the Ge content rises, while simultaneously inducing a magnetocrystalline anisotropy at room temperature. Powder X-ray diffraction on oriented samples indicates that Fe<sub>1.95</sub>P<sub>1-<em>x</em></sub>Ge<sub><em>x</em></sub> (0 ≤ <em>x</em> ≤ 0.1) exhibits a <em>c</em>-axis easy magnetic axis.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"173 ","pages":"Article 108183"},"PeriodicalIF":3.3,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.solidstatesciences.2025.108174
Jagoda Budnik, Maria Gazda, Tadeusz Miruszewski
In this work, a group of mixed ionic-electronic conductors, SrFe1-xCoxO3-δ (x = 0, 0.4, 0.6, 0.8), synthesised with NiO as a sintering aid was studied. The total electrical conductivity as a function of temperature was analysed using the DC-4W method. All investigated materials exhibited a maximum conductivity at temperatures between 620 and 870 K. Thermally activated conduction below- and metal-like conductivity behaviour above the maximum temperature was observed. Seebeck coefficient measurements of SrFe1-xCoxO3-δ (x = 0, 0.4, 0.6, 0.8) showed that all materials exhibited a p-type electronic conductivity in air. Furthermore, thermoelectric studies have enabled the determination of temperature dependencies of electron hole concentration and their mobility. With higher Co content in the materials, the Seebeck coefficient was lower, while the concentration of electron holes increased. With increasing temperature, the concentration of electron holes declined in all materials due to thermal reduction.
{"title":"Electrical and thermoelectric transport of SrFe1-xCoxO3-δ mixed-conducting perovskites","authors":"Jagoda Budnik, Maria Gazda, Tadeusz Miruszewski","doi":"10.1016/j.solidstatesciences.2025.108174","DOIUrl":"10.1016/j.solidstatesciences.2025.108174","url":null,"abstract":"<div><div>In this work, a group of mixed ionic-electronic conductors, SrFe<sub>1-x</sub>Co<sub>x</sub>O<sub>3-δ</sub> (x = 0, 0.4, 0.6, 0.8), synthesised with NiO as a sintering aid was studied. The total electrical conductivity as a function of temperature was analysed using the DC-4W method. All investigated materials exhibited a maximum conductivity at temperatures between 620 and 870 K. Thermally activated conduction below- and metal-like conductivity behaviour above the maximum temperature was observed. Seebeck coefficient measurements of SrFe<sub>1-x</sub>Co<sub>x</sub>O<sub>3-δ</sub> (x = 0, 0.4, 0.6, 0.8) showed that all materials exhibited a p-type electronic conductivity in air. Furthermore, thermoelectric studies have enabled the determination of temperature dependencies of electron hole concentration and their mobility. With higher Co content in the materials, the Seebeck coefficient was lower, while the concentration of electron holes increased. With increasing temperature, the concentration of electron holes declined in all materials due to thermal reduction.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"173 ","pages":"Article 108174"},"PeriodicalIF":3.3,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carbon materials derived from conjugated polymers have been considered as potential candidate for energy devices due to their efficient processibility, high carbonization yield, high nitrogen content, and good conductivity. Poly(phenylenediamine) (para, ortho and meta derivatives) polymers offer multifunctionality owing to the presence of one free amino group per repetitive unit. Here, we report fabrication of carbon nanofiber aerogel derived from poly(para-phenylenediamine) (PpPD) using polyvinyl alcohol (PVA) as the gelation and structure directing template for the nanofibrous aerogel structure. The overall carbon yield is as high as 40 % with nitrogen content of 11 %. The obtained carbon aerogel structure exhibited unique fibrous morphology with sponge-like porous structure and specific surface area of 339 m2 g−1. As a supercapacitor electrode, the material could deliver a high specific capacitance of 452 F g−1 at 1 A g−1 in 1 M H2SO4 electrolyte. The electrode also demonstrated excellent cycling stability, retaining up to 97 % of its capacity over 4500 cycles. In addition, as a prospective adsorbent material for methylene blue (MB) dye, the material showed shorter contact time in achieving the adsorption equilibrium compared to various derived-carbon aerogels and graphene-based carbon aerogels. The excellent electrochemical performance and adsorption efficiency showed the potential application of this material for energy storage and environmental applications.
共轭聚合物衍生的碳材料因其加工效率高、碳化率高、含氮量高和导电性好而被认为是潜在的能源器件候选材料。聚（苯二胺）（对位、邻位和间位衍生物）聚合物由于每个重复单元存在一个游离氨基而具有多功能性。本文报道了以聚对苯二胺（PpPD）为原料，以聚乙烯醇（PVA）为凝胶和结构导向模板制备纳米纤维气凝胶。总碳产量高达40%，含氮量为11%。所得的碳气凝胶结构具有独特的纤维形态，具有海绵状多孔结构，比表面积为339 m2 g−1。作为超级电容器电极，该材料在1 M H2SO4电解质中，在1 a g−1条件下可提供452 F g−1的高比电容。该电极还表现出优异的循环稳定性，在4500次循环中保持高达97%的容量。此外，与各种衍生碳气凝胶和石墨烯基碳气凝胶相比，该材料在达到吸附平衡时的接触时间更短，是一种有前景的亚甲基蓝（MB）染料的吸附材料。优异的电化学性能和吸附效率显示了该材料在储能和环境方面的潜在应用。
{"title":"Poly(para-phenylenediamine) - derived carbon nanofiber aerogel for energy storage and environmental applications","authors":"Partha Pratim Sarma , Rohit Kumar Gupta , Rimpi Chakravarty , Basanta Kumar Rajbongshi , Ashish Kumar Mishra , Jaidev , Mridula Baro","doi":"10.1016/j.solidstatesciences.2025.108181","DOIUrl":"10.1016/j.solidstatesciences.2025.108181","url":null,"abstract":"<div><div>Carbon materials derived from conjugated polymers have been considered as potential candidate for energy devices due to their efficient processibility, high carbonization yield, high nitrogen content, and good conductivity. Poly(phenylenediamine) (para, ortho and meta derivatives) polymers offer multifunctionality owing to the presence of one free amino group per repetitive unit. Here, we report fabrication of carbon nanofiber aerogel derived from poly(<em>para</em>-phenylenediamine) (P<em>p</em>PD) using polyvinyl alcohol (PVA) as the gelation and structure directing template for the nanofibrous aerogel structure. The overall carbon yield is as high as 40 % with nitrogen content of 11 %. The obtained carbon aerogel structure exhibited unique fibrous morphology with sponge-like porous structure and specific surface area of 339 m<sup>2</sup> g<sup>−1</sup>. As a supercapacitor electrode, the material could deliver a high specific capacitance of 452 F g<sup>−1</sup> at 1 A g<sup>−1</sup> in 1 M H<sub>2</sub>SO<sub>4</sub> electrolyte. The electrode also demonstrated excellent cycling stability, retaining up to 97 % of its capacity over 4500 cycles. In addition, as a prospective adsorbent material for methylene blue (MB) dye, the material showed shorter contact time in achieving the adsorption equilibrium compared to various derived-carbon aerogels and graphene-based carbon aerogels. The excellent electrochemical performance and adsorption efficiency showed the potential application of this material for energy storage and environmental applications.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"172 ","pages":"Article 108181"},"PeriodicalIF":3.3,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The dobrovolskyite-type Na4Ca(SO4)3 compound was obtained by rapid cooling of a melt. Crystal structure was solved and refined using single crystal X-ray diffraction (SCXRD) data (R3, a = 15.7355(3), c = 22.4023(5) Å, V = 4803.8(2) Å3, R1 = 0.053). The thermal behavior of Na4Ca(SO4)3 was investigated using high-temperature powder X-ray diffraction (HTPXRD) from 30 to 840 °C. The HTPXRD data reveal a reversible R3 ↔ P63/mmc phase transition at 280 °C. The crystal structure of the high-temperature polymorph (P63/mmc) was refined via the Rietveld method using data collected at 820 °C (P63/mmc, a = 5.38706(6), c = 7.82774(2) Å, V = 196.731(1) Å3, Z = 2, R1 = 0.060). The low-temperature Na4Ca(SO4)3 (R3) polymorph exhibits highly anisotropic thermal expansion between 30 and 270 °C (αa = 26(1), αc = 53 (1), αV = 105 (2) × 10 −6 °C–1 at 30 °C). Bond-valence energy landscape (BVEL) maps, constructed using the crystal structure data for both polymorphs, predict potential Na+ migration pathways. The calculated activation energies for migration at 30 °C are 1.64 eV within the ab plane and 1.61 eV along the c axis. Experimentally, the electrical conductivity is 5.89 × 10−6 S/cm at 200 °C for the low-temperature modification and increases significantly to 7.06 × 10−2 S/cm at 600 °C for the high-temperature modification. The activation energies Ea for electrical conductivity are 1.21(4) eV and 0.49(2) eV for both polymorphs, respectively.
采用熔体快速冷却法制备了多布罗沃斯基型Na4Ca(SO4)3化合物。利用单晶x射线衍射（SCXRD）数据(R3, a = 15.7355(3), c = 22.4023（5) Å， V = 4803.8(2) Å3, R1 = 0.053）对晶体结构进行求解和细化。采用高温粉末x射线衍射（HTPXRD）研究了Na4Ca(SO4)3在30 ~ 840℃范围内的热行为。HTPXRD数据显示在280°C时存在可逆的R3↔P63/mmc相变。利用820℃(P63/mmc, a = 5.38706(6), C = 7.82774（2) Å， V = 196.731(1) Å3, Z = 2, R1 = 0.060）收集的数据，采用Rietveld法对高温晶型（P63/mmc）的晶体结构进行了精化。低温Na4Ca(SO4)3 （R3）多晶体在30 ~ 270℃之间表现出高度的各向异性热膨胀(αa = 26(1), αc = 53 （1), αV = 105 (2) × 10−6℃- 1）。利用两种多晶的晶体结构数据构建的键价能景观（BVEL）图预测了潜在的Na+迁移途径。在30°C时，沿ab平面和C轴的迁移活化能分别为1.64 eV和1.61 eV。实验结果表明，低温改性的导电率在200℃时为5.89 × 10−6 S/cm，高温改性的导电率在600℃时达到7.06 × 10−2 S/cm。两种晶型的电导率活化能Ea分别为1.21(4)eV和0.49(2)eV。
{"title":"A dobrovolskyite-type Na4Ca(SO4)3 sulfate: structural phase transition, thermal expansion and ionic conductivity","authors":"A.P. Shablinskii , O. Yu Shorets , Y.P. Biryukov , N.A. Melnikova , M.S. Avdontceva , R.S. Bubnova , A.V. Povolotskiy , M.G. Krzhizhanovskaya , V.L. Ugolkov , I.V. Murin , S.K. Filatov","doi":"10.1016/j.solidstatesciences.2025.108178","DOIUrl":"10.1016/j.solidstatesciences.2025.108178","url":null,"abstract":"<div><div>The dobrovolskyite-type Na<sub>4</sub>Ca(SO<sub>4</sub>)<sub>3</sub> compound was obtained by rapid cooling of a melt. Crystal structure was solved and refined using single crystal X-ray diffraction (SCXRD) data (<em>R</em>3, <em>a</em> = 15.7355(3), <em>c</em> = 22.4023(5) Å, <em>V</em> = 4803.8(2) Å<sup>3</sup>, <em>R</em><sub>1</sub> = 0.053). The thermal behavior of Na<sub>4</sub>Ca(SO<sub>4</sub>)<sub>3</sub> was investigated using high-temperature powder X-ray diffraction (HTPXRD) from 30 to 840 °C. The HTPXRD data reveal a reversible <em>R</em>3 ↔ <em>P</em>6<sub>3</sub>/<em>mmc</em> phase transition at 280 °C. The crystal structure of the high-temperature polymorph (<em>P</em>6<sub>3</sub>/<em>mmc</em>) was refined <em>via</em> the Rietveld method using data collected at 820 °C (<em>P</em>6<sub>3</sub>/<em>mmc, a</em> = 5.38706(6), <em>c</em> = 7.82774(2) Å, <em>V</em> = 196.731(1) Å<sup>3</sup>, <em>Z</em> = 2, <em>R</em><sub>1</sub> = 0.060). The low-temperature Na<sub>4</sub>Ca(SO<sub>4</sub>)<sub>3</sub> (<em>R</em>3) polymorph exhibits highly anisotropic thermal expansion between 30 and 270 °C (α<sub><em>a</em></sub> = 26(1), α<sub><em>c</em></sub> = 53 (1), α<sub><em>V</em></sub> = 105 (2) × 10 <sup>−6</sup> °C<sup>–1</sup> at 30 °C). Bond-valence energy landscape (BVEL) maps, constructed using the crystal structure data for both polymorphs, predict potential Na<sup>+</sup> migration pathways. The calculated activation energies for migration at 30 °C are 1.64 eV within the <em>ab</em> plane and 1.61 eV along the <em>c</em> axis. Experimentally, the electrical conductivity is 5.89 × 10<sup>−6</sup> S/cm at 200 °C for the low-temperature modification and increases significantly to 7.06 × 10<sup>−2</sup> S/cm at 600 °C for the high-temperature modification. The activation energies E<sub>a</sub> for electrical conductivity are 1.21(4) eV and 0.49(2) eV for both polymorphs, respectively.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"173 ","pages":"Article 108178"},"PeriodicalIF":3.3,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145735823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-09DOI: 10.1016/j.solidstatesciences.2025.108180
Chuanyue Yang , Mengmeng Yu , Yan Liu , Bohui Cui , Longjiang Sun , Jingquan Sha
Hard carbon (HC) as anode for sodium-ion batteries (SIBs) has been extensively investigated, and heteroatom doping is a proven strategy to enhance HC performance. Herein, series of N, P, and S co-doping HCs (NPS-HCs-Ts, s = 700, 800, 900) from a single-source polyphosphazene copolymer, poly(cyclotriphosphazene-co-4,4′-dihydroxydiphenyl sulfone) (PZS) were synthesized by adjusting the calcination temperature. This molecular design ensures the homogeneous incorporation of N, P, and S directly into the carbon framework, where N-doping creates favorable sites for Na+ adsorption, P-doping expands the interlayer spacing, while S-doping further modulates the electronic structure. Due to the internally released volatile gases (foaming effect) outcompete the tendencies toward contraction, densification, and melt-induced agglomeration at 800 °C, the resulting NPS-HCs-800 anode for SIBs delivers a high reversible capacity of 498 mAh g−1 at 100 mA g−1 along with exceptional long-term cycling stability (204 mAh g−1 after 1000 cycles at 1000 mA g−1). This work provides a novel precursor design strategy for crafting multi-heteroatom-doped carbon anodes with superior performance for advanced SIBs.
硬碳（HC）作为钠离子电池（sib）的阳极已经得到了广泛的研究，杂原子掺杂是提高硬碳性能的一种行之有效的策略。本文以单源聚磷腈共聚物聚（环三磷腈-co-4,4′-二羟基二苯砜）（PZS）为原料，通过调节煅烧温度合成了N、P、S共掺杂的hc系列（NPS-HCs-Ts, S = 700、800、900）。这种分子设计确保了N， P和S直接均匀地结合到碳框架中，其中N掺杂为Na+吸附创造了有利的位置，P掺杂扩大了层间间距，而S掺杂进一步调节了电子结构。由于内部释放的挥发性气体（发泡效应）在800°C时优于收缩、致密化和熔体诱导结块的趋势，因此用于sib的NPS-HCs-800阳极在100 mA g- 1时具有498 mAh g- 1的高可逆容量，并且具有出色的长期循环稳定性（在1000 mA g- 1下循环1000次后具有204 mAh g- 1）。这项工作为制造具有优异性能的先进sib多杂原子掺杂碳阳极提供了一种新的前驱体设计策略。
{"title":"Single-source polyphosphazene-derived N, P, S co-doping HCs for high-performance SIBs anode","authors":"Chuanyue Yang , Mengmeng Yu , Yan Liu , Bohui Cui , Longjiang Sun , Jingquan Sha","doi":"10.1016/j.solidstatesciences.2025.108180","DOIUrl":"10.1016/j.solidstatesciences.2025.108180","url":null,"abstract":"<div><div>Hard carbon (HC) as anode for sodium-ion batteries (SIBs) has been extensively investigated, and heteroatom doping is a proven strategy to enhance HC performance. Herein, series of N, P, and S co-doping HCs (NPS-HCs-Ts, s = 700, 800, 900) from a single-source polyphosphazene copolymer, poly(cyclotriphosphazene-co-4,4′-dihydroxydiphenyl sulfone) (PZS) were synthesized by adjusting the calcination temperature. This molecular design ensures the homogeneous incorporation of N, P, and S directly into the carbon framework, where N-doping creates favorable sites for Na<sup>+</sup> adsorption, P-doping expands the interlayer spacing, while S-doping further modulates the electronic structure. Due to the internally released volatile gases (foaming effect) outcompete the tendencies toward contraction, densification, and melt-induced agglomeration at 800 °C, the resulting NPS-HCs-800 anode for SIBs delivers a high reversible capacity of 498 mAh g<sup>−1</sup> at 100 mA g<sup>−1</sup> along with exceptional long-term cycling stability (204 mAh g<sup>−1</sup> after 1000 cycles at 1000 mA g<sup>−1</sup>). This work provides a novel precursor design strategy for crafting multi-heteroatom-doped carbon anodes with superior performance for advanced SIBs.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"173 ","pages":"Article 108180"},"PeriodicalIF":3.3,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145718557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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