Journal of Solid State Chemistry最新文献

{"title":"Elucidation of augmented visible-light photocatalysis in surface-modified coloured rutile TiO2","authors":"A.V. Nimmy ,&nbsp;J. Indujalekshmi ,&nbsp;S. Chithra ,&nbsp;V.M. Anandakumar ,&nbsp;V. Biju","doi":"10.1016/j.jssc.2025.125685","DOIUrl":"10.1016/j.jssc.2025.125685","url":null,"abstract":"<div><div>The prevalent TiO₂ photocatalysts have some glaring limitations, viz., (i) their inactivity under visible light irradiation and (ii) the irreversible temperature-dependent transformation of photocatalytically active anatase phase into inactive rutile. In this study, we employed a facile method to develop visible-light sensitive coloured rutile photocatalysts to tackle these issues. Here, we executed a surface modification technique on sol-gel derived, crystalline rutile TiO₂ using sodium borohydride (NaBH₄). This was done in favourable atmospheric conditions, rendering it cost-effective and scalable. A series of rutile TiO₂ samples, with colour varied from white to black, were prepared by changing the amount of NaBH₄. Surface-modified samples exhibited crystalline core and disordered shell heterostructure. The pristine rutile sample was rich in Ti³⁺ and doubly charged oxygen vacancy V_o⁺⁺, respectively corresponding to shallow and deep defect states. In contrast, the surface-modified samples are rich in photocatalytically active shallow-trapped surface Ti³⁺ and singly charged oxygen vacancy (V_o⁺) defects, which act as colour centers. Hence, the photocatalytic activities of the surface-modified rutile TiO₂ enhanced significantly upon white LED irradiation. Amongst a series of surface-modified samples, rR3 (treated with 0.1 g of NaBH₄) showed the highest visible-light photocatalytic degradation rate constant (10.35 × 10⁻³ min⁻¹) for methylene blue (MB) dye. In addition to MB, sample rR3 showed better degradation of rhodamine B (RhB) and phenol than the pure rutile and commercial photocatalyst Degussa P25 under visible-light irradiation. Since rutile is the thermodynamically stable form of TiO₂, surface-modified samples could be effective in high-temperature applications, especially without the assistance of regularly utilized UV radiation.</div></div>","PeriodicalId":378,"journal":{"name":"Journal of Solid State Chemistry","volume":"353 ","pages":"Article 125685"},"PeriodicalIF":3.5,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217150","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}

{"title":"A zwitterionic pyridine-carboxylate Cd(II) MOF for dual-function environmental remediation: Iodine capture and selective Cr2O72− luminescent sensing","authors":"Yu-Jie Zhang,&nbsp;Hui-Qi Xie,&nbsp;Sheng-Run Zheng,&nbsp;Hai-Yan Song","doi":"10.1016/j.jssc.2025.125683","DOIUrl":"10.1016/j.jssc.2025.125683","url":null,"abstract":"<div><div>A new Cd(II)-based MOF, namely, {[Cd(CIPA)₂]·2DMF·H₂O}_n (cc, HCIPA = 1-(4-carboxyphenyl)pyridin-1-ium-4-yl)(pyridin-4-yl)amide), was constructed on the basis of a new zwitterionic pyridine-carboxylate ligand. Single-crystal X-ray analysis revealed that Cd-CIPA has a 3D supramolecular framework with bilayer 2D networks stabilized by weak π‒π interactions, featuring 1D channels occupied by solvent molecules. By removing the guest molecules, the iodine adsorption property of activated Cd-CIPA was studied. This material has an iodine vapor adsorption capacity of 3.2 g/g, which is attributed to strong charge‒transfer interactions between iodine and N/O-containing moieties in the framework. Additionally, Cd-CIPA functions as a selective fluorescent sensor for aqueous Cr₂O₇²⁻ detection, where quenching is governed primarily by the inner filter effect. This work highlights the dual functionality of zwitterionic ligand-derived MOFs for simultaneous pollutant capture and sensing.</div></div>","PeriodicalId":378,"journal":{"name":"Journal of Solid State Chemistry","volume":"353 ","pages":"Article 125683"},"PeriodicalIF":3.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155089","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}

{"title":"Investigation of ionic conductivity and relaxation in mechanochemical synthesized AlI3-doped Li4SnS4 amorphous solid electrolyte","authors":"Nguyen Huu Huy Phuc ,&nbsp;Anh-Tu Tran ,&nbsp;Viet-Toan Tran ,&nbsp;Vinh-Dat Vuong ,&nbsp;Pham Tan Thi","doi":"10.1016/j.jssc.2025.125679","DOIUrl":"10.1016/j.jssc.2025.125679","url":null,"abstract":"<div><div>Amorphous (100-x)Li₄SnS₄−xAlI₃ solid electrolytes (SEs) were prepared via mechanochemical synthesis to study the effect of AlI₃ doping on the ionic conductivity and Li-ion dynamics in amorphous Li₄SnS₄. The structure of the samples was characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS). The ionic conductivity of amorphous 93.33Li₄SnS₄-6.67AlI₃ was ∼1.2 × 10⁻⁴ S cm⁻¹ at 30 °C, comparable to that of reported Li₄SnS₄-based SEs. The effect of AlI₃ doping on the conductivity and dielectric properties of the samples was studied through alternating current (AC) impedance spectroscopy analysis. The conductivity analysis suggested that ion formation was the main contributor to the conductivity barrier in the prepared SEs. The developed strategy improved the ionic conductivity of the amorphous Li₄SnS₄ solid electrolyte.</div></div>","PeriodicalId":378,"journal":{"name":"Journal of Solid State Chemistry","volume":"353 ","pages":"Article 125679"},"PeriodicalIF":3.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119410","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}

{"title":"Energy transfer engineering in matrix-sensitized NaBa10Y5W4O30: Sm3+ orange-red phosphors for solid-state lighting","authors":"Funi Liu ,&nbsp;Jin Zhao ,&nbsp;Ruting Tu ,&nbsp;Yongcheng Fu ,&nbsp;Yu Wang ,&nbsp;Jingwen Lu ,&nbsp;Zhihua Leng","doi":"10.1016/j.jssc.2025.125681","DOIUrl":"10.1016/j.jssc.2025.125681","url":null,"abstract":"<div><div>A sequence of matrix-sensitized NaBa₁₀Y₅W₄O₃₀: <em>x</em>Sm³⁺ (<em>x</em> = 0.01–0.09) orange-red phosphors was successfully fabricated using a high-temperature solid-state reaction method. Their structural and luminescence properties were systematically characterized by XRD, SEM, photoluminescence spectroscopy, fluorescence lifetime measurements, temperature-dependent PL measurements, and CIE chromaticity coordinate analysis. XRD analysis verified the successful synthesis of phase-pure compounds, with the successful incorporation of Sm³⁺ ions causing no significant lattice distortion. SEM images combined with EDS mapping verified the homogeneous distribution of all constituent elements throughout the sample. Under 348 nm UV excitation, NaBa₁₀Y₅W₄O₃₀: Sm³⁺ phosphor exhibited its characteristic emission peak at 579 nm, corresponding to the ⁴G_5/2 → ⁶H_5/2 transition of Sm³⁺. The emission intensity attained its peak value at <em>x</em> = 0.05, beyond which concentration quenching occurred via electric dipole-dipole interactions among Sm³⁺ ions. This observation was accompanied by a gradual reduction in fluorescence lifetime as the Sm³⁺ ion concentration increased. Furthermore, CIE chromaticity coordinates remained steady in the orange-red light area, and variable-temperature spectra in the 298–423 K range demonstrated exceptional thermal stability. Warm-white light emission properties were confirmed by the CIE chromaticity coordinates of (0.3514, 0.3800) for the packed warm-white LED device. These results demonstrate that NaBa₁₀Y₅W₄O₃₀: Sm³⁺ orange-red phosphor possesses considerable promise for applications in white LED lighting.</div></div>","PeriodicalId":378,"journal":{"name":"Journal of Solid State Chemistry","volume":"353 ","pages":"Article 125681"},"PeriodicalIF":3.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155090","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}

{"title":"CuFe2O4 particles decorated on NiO nanosheets for high performance semi-solid supercapacitor","authors":"Amal BaQais ,&nbsp;Mohammad Shariq ,&nbsp;Eman M. Alshehri ,&nbsp;M.D. Alshahrani ,&nbsp;Faris Alfifi ,&nbsp;F.H. Al-abdali ,&nbsp;A. Khatab ,&nbsp;Imtiaz Ahmed","doi":"10.1016/j.jssc.2025.125680","DOIUrl":"10.1016/j.jssc.2025.125680","url":null,"abstract":"<div><div>Transition metal oxides and ferrite-based nanostructures have emerged as desirable candidates for electrode materials in energy storage systems, particularly supercapacitors. This is primarily due to their unique combination of advantageous properties, including superior electrochemical stability, efficient mixed ionic-electronic conductivity, cost-effectiveness, and eco-friendliness. These features make them well-suited for sustainable energy technologies. In the current study, a CuFe₂O₄/NiO composite was successfully prepared using a one-step hydrothermal method. The electrochemical studies revealed outstanding charge storage capability, with the CuFe₂O₄/NiO composite delivering a high specific capacitance (Csp) of ∼348 F/g at a current density of 1 A/g. The electrode delivered an energy density (E_D) of 20.25 Wh/kg with a corresponding power density (P_D) of 565 W/kg, highlighting its promising capability for energy storage. This enhanced electrochemical response is attributed to the cooperative effect between the CuFe₂O₄ and NiO phases. This synergy not only improves the electrical conductivity but also imparts magnetic responsiveness, which may offer additional benefits in functional device integration. Overall, these findings highlight the potential of CuFe₂O₄/NiO nanocomposites as suitable materials for next-generation electrochemical energy applications, especially in SC technologies.</div></div>","PeriodicalId":378,"journal":{"name":"Journal of Solid State Chemistry","volume":"353 ","pages":"Article 125680"},"PeriodicalIF":3.5,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119411","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}

{"title":"Fe2O3/LaFeO3 nanocomposites derived from MOFs as high-performance anodes for lithium-ion batteries","authors":"Tian-Jiao Jiang ,&nbsp;Yu-Nan Cui ,&nbsp;Li Liu ,&nbsp;Gang Yang ,&nbsp;Peng-Fei Wang ,&nbsp;Yu-Hang Zhang ,&nbsp;Li-Yan Tian ,&nbsp;Yun-Heng Li ,&nbsp;Fa-Nian Shi","doi":"10.1016/j.jssc.2025.125676","DOIUrl":"10.1016/j.jssc.2025.125676","url":null,"abstract":"<div><div>Metal-organic frameworks (MOFs), as an emerging porous material, have attracted much attention due to their extremely large specific surface area and extremely high porosity. In recent years, the synthesis of transition metal oxides (TMOs) using MOFs as precursors has become a research hotspot. However, the iron oxide (Fe_xO_y) compounds derived from Fe-MOFs still face problems such as low electrical conductivity and significant volume changes during charging and discharging in practical applications. For this purpose, in this study, the Fe–La-MOFs precursors were prepared by solvothermal method, and nanocomposites of Fe₂O₃, 10Fe₂O₃/LaFeO₃, 20Fe₂O₃/LaFeO₃ and 30Fe₂O₃/LaFeO₃ were synthesized by calcination of the as-prepared MOFs. By introducing the inexpensive rare earth element La, the lithium storage performance and structural stability of the material have been effectively enhanced. The experimental results show that at the optimal doping ratio, the 20Fe₂O₃/LaFeO₃ composite material exhibits excellent electrochemical performance, with a reversible capacity of up to 742.59 mAh g⁻¹ (after 100 cycles), which is much higher than 407.1 mAh g⁻¹ of pure Fe₂O₃. Importantly, the presence of LaFeO₃ enables the material to maintain 616.39 mAh g⁻¹ at 1 A g⁻¹, which effectively alleviates the volume expansion problem of Fe₂O₃ materials during the charging and discharging process. The 20Fe₂O₃/LaFeO₃ nanocomposites derived from iron-based MOFs are expected to become an ideal choice for high-performance lithium-ion battery anode materials due to their outstanding electrochemical performance and promising application prospects.</div></div>","PeriodicalId":378,"journal":{"name":"Journal of Solid State Chemistry","volume":"353 ","pages":"Article 125676"},"PeriodicalIF":3.5,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109570","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}

{"title":"Enhanced luminescence and negative thermal quenching in Bi3+/Tb3+ Co-doped KYF4 green phosphor","authors":"Yi Zhang ,&nbsp;Haoyang Ren ,&nbsp;Mingjie Huang ,&nbsp;Yongxing Liang ,&nbsp;Lei Hou ,&nbsp;Danyu Liao ,&nbsp;Sen Liao ,&nbsp;Yingheng Huang","doi":"10.1016/j.jssc.2025.125669","DOIUrl":"10.1016/j.jssc.2025.125669","url":null,"abstract":"<div><div>Despite the broad application of phosphors in lighting technologies, they still face considerable limitations in thermal stability. A novel green-emitting KYF₄:Tb³⁺,Bi³⁺ phosphor was successfully synthesised via a hydrothermal approach, exhibiting superior photoluminescence performance and enhanced thermal stability. The material achieved an absolute photoluminescence quantum yield of 59.74 %. The incorporation of Bi³⁺ ions enabled efficient energy transfer to Tb³⁺ centres, resulting in a 1.5-fold increase in green emission compared to the Tb³⁺-only doped sample. Thermoluminescence and activation energy analyses revealed that Bi³⁺/Tb³⁺ co-doping introduced deeper trap states, increased trap concentration, and a higher thermal activation energy (E_a = 0.47 eV), all contributing to improved thermal stability. Notably, the phosphor maintained nearly constant emission intensity at temperatures up to 443 K. Furthermore, prototype white light-emitting diodes fabricated using the synthesised phosphor exhibited high-quality white light emission under a 10 mA driving current, characterised by an excellent correlated colour temperature and a suitable colour rendering index for lighting applications. These findings demonstrate that Bi³⁺ co-doping is an effective strategy for enhancing both luminescence efficiency and thermal stability in rare-earth-based phosphors, offering valuable insights for the development of advanced solid-state optical materials.</div></div>","PeriodicalId":378,"journal":{"name":"Journal of Solid State Chemistry","volume":"353 ","pages":"Article 125669"},"PeriodicalIF":3.5,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109568","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}

{"title":"Visible light mediated photocatalytic conversion of nitroaromatics to aminoaromatics employing a P doped g-C3N4/CuFe2O4 nanocomposite","authors":"Ali Oji Moghanlou ,&nbsp;Amir Beyghzadeh ,&nbsp;Sona Jamshidi","doi":"10.1016/j.jssc.2025.125678","DOIUrl":"10.1016/j.jssc.2025.125678","url":null,"abstract":"<div><div>This study reports the successful preparation of P-doped g-C₃N₄/CuFe₂O₄ nanocomposites using a co-precipitation method. The P-doped g-C₃N₄ material was synthesized through thermal calcination of melamine and diammonium hydrogen phosphate precursors, which allowed the effective incorporation of phosphorus atoms into the g-C₃N₄ structure. Afterwards, CuFe₂O₄ nanoparticles were successfully combined with the P-doped g-C₃N₄ layers through a hydrothermal process. Various characterization techniques, including FTIR, XRD, XPS, FESEM, TEM, EDS, elemental mapping, DRS, BET, PL, and EIS, were applied to study the structure, morphology, and optical properties of the nanocomposites. In this work, we present a simple, eco-friendly, and controllable synthesis approach for producing highly efficient P-doped g-C₃N₄/CuFe₂O₄ composites for environmental purification purposes. The prepared nanocomposites showed a significant improvement in photocatalytic performance for reducing nitroaromatic compounds under visible light compared to the original materials. Among them, the P-doped g-C₃N₄/CuFe₂O₄-40 % composite achieved a complete conversion of nitrobenzene to aniline within 60 min with a yield of 100 %. Hydrazine monohydrate was used as the hydrogen source in these reactions. Moreover, the catalyst maintained its high efficiency and stable structure over twelve repeated cycles without noticeable loss of activity, demonstrating excellent stability and reusability.</div></div>","PeriodicalId":378,"journal":{"name":"Journal of Solid State Chemistry","volume":"353 ","pages":"Article 125678"},"PeriodicalIF":3.5,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106688","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}

{"title":"A coordination polymer based on mixed ligand strategy: Synthesis, structural investigation, and fluorescence performance","authors":"Jiu-Zhou Zhao ,&nbsp;Xiao Yan ,&nbsp;Zan Sun","doi":"10.1016/j.jssc.2025.125677","DOIUrl":"10.1016/j.jssc.2025.125677","url":null,"abstract":"<div><div>A coordination polymer, [Mn(SCND²⁻)(4,4′-Dm-2,2′-bpy)(H₂O)₂]_n (<strong>Mn-CP</strong>), based on 4-sulfo-<em>N</em>-(4-carboxyphenyl) naphthalene-1,8-dicarboximide (H₂SCND) and 4,4′-Dimethyl-2,2′-bipyridine (4,4′-Dm-2,2′-bpy) ligands has been successfully synthesized. The single-crystal X-ray diffraction (SCXRD) reveals that <strong>Mn-CP</strong> crystallizes in the <em>P</em>1 space group of the triclinic crystal system. In this structure, 1D chain structures are formed by SCND²⁻ ligands and metal centers, in which 4,4′-Dm-2,2′-bpy act as a capping ligand. These chains are further connected through hydrogen bonds and π···π interactions, forming a three-dimensional (3D) supramolecular structure. <strong>Mn-CP</strong> exhibits excellent photoluminescence with high stability. Notably, it can selectively detect Cr₂O₇²⁻ / <em>o</em>-NA (<em>o</em>-nitroaniline) / <em>p</em>-NP (<em>p</em>-nitrophenol) / Norfloxacin (NFX) / Nitrofurazone (NFZ) in solution, with excellent selectivity and recyclability. The sensing mechanism likely involves fluorescence resonance energy transfer and competitive absorption, as indicated by experimental results. This work provides a new method for detecting hazardous substances in solution.</div></div>","PeriodicalId":378,"journal":{"name":"Journal of Solid State Chemistry","volume":"353 ","pages":"Article 125677"},"PeriodicalIF":3.5,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106689","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}

{"title":"Structural and spectroscopic insights of medium-entropy Na2-uNi2+2-xNi3+x(Cr3+1-yCr4+y)1-wFe3+w(PO4)3 cathodes with sodium-ion insertion","authors":"Rihab Trimech ,&nbsp;Khalifa Souiwa ,&nbsp;Bo Song ,&nbsp;Zhanhua Wei ,&nbsp;Mourad Hidouri ,&nbsp;Brahim Ayed ,&nbsp;Ruqin Ma ,&nbsp;Yong Yang ,&nbsp;Gregorio F. Ortiz","doi":"10.1016/j.jssc.2025.125675","DOIUrl":"10.1016/j.jssc.2025.125675","url":null,"abstract":"<div><div>Medium-entropy phosphate cathode materials with an α-CrPO₄-type structure exhibit promising potential for Na-ion insertion. Fe-substituted Na_2-uNi²⁺_2-xNi³⁺_x(Cr³⁺_1-yCr⁴⁺_y)_1-wFe³⁺_w(PO₄)₃ (where u = x + y and w = 0, 0.5, and 1) were synthesized via a modified Pechini method. Rietveld refinement of the X-ray diffraction patterns confirmed the stoichiometries Na_1.7Ni²⁺_1.9Ni³⁺_0.1Cr³⁺_0.8Cr⁴⁺_0.2(PO₄)₃, Na_1.6Ni²⁺_1.7Ni³⁺_0.3Cr³⁺_0.4Cr⁴⁺_0.1Fe³⁺_0.5(PO₄)₃ and Na_1.8Ni²⁺_1.8Ni³⁺_0.2Fe³⁺(PO₄)₃. Although structurally similar to the α-Na₂Ni₂Fe(PO₄)₃, these materials display distinct atomic site coordinates and occupancies, with transition metals M(1) and M(2) (M = Fe, Ni, Cr) statistically disordered across 4a and 8g sites. Electrochemical performance was evaluated within a moderate voltage range of 1.00–3.75 V vs. Na⁺/Na. Due to the initially low sodium content, with partial occupation of 4b sites and empty 4c sites, the first discharge cycle yielded specific capacities of 165.8, 188.9, and 205.34 mA h g⁻¹, with reversibility rates of 80.1, 84.1, and 90 %, respectively. Ex-situ X-ray diffraction patterns, X-ray photoelectron spectroscopy, and Cr and Ni–K edge X-ray absorption near edge structure analyses confirmed the occurrence of Na-ion insertion reactions, ruling out conversion reaction. The materials demonstrated reversible multi-electron reactions involving moderate activation of Cr⁴⁺/Cr³⁺/Cr²⁺, Fe³⁺/Fe²⁺/Fe⁰, and Ni³⁺/Ni²⁺/Ni⁰ redox couples while preserving the structure. Ultimately, Fe substitution effectively suppressed phase transitions and enhanced structural reversibility.</div></div>","PeriodicalId":378,"journal":{"name":"Journal of Solid State Chemistry","volume":"353 ","pages":"Article 125675"},"PeriodicalIF":3.5,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155672","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}