{"title":"Single-Phase Solid-Solution Reaction Facilitated Sodium-Ion Storage in Indium-Substituted Monoclinic Sodium-Iron Phosphomolybdate Cathodes","authors":"Sharad Dnyanu Pinjari, Purandas Mudavath, Ravi Chandra Dutta, Ipsita Pal, Dipan Kundu, Saikumar Parshanaboina, Anand Kumar Singh, Ashok Kumar Nanjundan, Rohit Ranganathan Gaddam","doi":"10.1002/smll.202501004","DOIUrl":null,"url":null,"abstract":"<p>Despite being a compelling alternative to the existing lithium-ion battery technology, the unavailability of cathodes with high energy density and capacity poses a key challenge toward the wider adaption of sodium-ion batteries (NIB). In this regard, iron-rich NASICONs have triggered significant attention owing to a greater abundance of Fe and higher operating voltages of Fe<sup>2+</sup>/Fe<sup>3+</sup> redox-couple. A major roadblock in such cathodes stems from the voltage hysteresis at higher current rates. Herein, a NASICON-type NaFe<sub>2-x</sub>In<sub>x</sub>(PO<sub>4</sub>)(MoO<sub>4</sub>)<sub>2</sub> (NFIPM) cathode is reported that shows a stable single-phase solid-solution reaction with significantly attenuated overpotential. Indium is strategically incorporated at the iron sites, expanding the lattice space to facilitate enhanced sodium-ion diffusion and also reducing the energy bandgap of NFIPM. <i>Magnetic susceptibility</i> (M-T) and <i>Electron Paramagnetic Resonance</i> (EPR) measurements reveal an increased spin state of iron following indium substitution. <i>First principle calculations</i> also confirm the lowering of the Na<sup>+</sup> migration energy barrier post indium doping. The optimized NFIPM10 shows a specific capacity of 111.85 mAh g<sup>−1</sup> at 0.1 C with remarkable cycling stability of up to 800 cycles at 2C. In situ X-ray diffraction confirms reversible structural stability of NFIPM during (de)sodiation, emphasizing the role of strategic doping in enhancing sodium-ion storage.</p>","PeriodicalId":228,"journal":{"name":"Small","volume":"21 18","pages":""},"PeriodicalIF":12.1000,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/smll.202501004","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Small","FirstCategoryId":"88","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/smll.202501004","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Despite being a compelling alternative to the existing lithium-ion battery technology, the unavailability of cathodes with high energy density and capacity poses a key challenge toward the wider adaption of sodium-ion batteries (NIB). In this regard, iron-rich NASICONs have triggered significant attention owing to a greater abundance of Fe and higher operating voltages of Fe2+/Fe3+ redox-couple. A major roadblock in such cathodes stems from the voltage hysteresis at higher current rates. Herein, a NASICON-type NaFe2-xInx(PO4)(MoO4)2 (NFIPM) cathode is reported that shows a stable single-phase solid-solution reaction with significantly attenuated overpotential. Indium is strategically incorporated at the iron sites, expanding the lattice space to facilitate enhanced sodium-ion diffusion and also reducing the energy bandgap of NFIPM. Magnetic susceptibility (M-T) and Electron Paramagnetic Resonance (EPR) measurements reveal an increased spin state of iron following indium substitution. First principle calculations also confirm the lowering of the Na+ migration energy barrier post indium doping. The optimized NFIPM10 shows a specific capacity of 111.85 mAh g−1 at 0.1 C with remarkable cycling stability of up to 800 cycles at 2C. In situ X-ray diffraction confirms reversible structural stability of NFIPM during (de)sodiation, emphasizing the role of strategic doping in enhancing sodium-ion storage.
尽管钠离子电池是现有锂离子电池技术的一个引人注目的替代方案,但高能量密度和高容量阴极的缺乏对钠离子电池(NIB)的广泛应用构成了关键挑战。在这方面,富铁nasicon由于铁的丰度更高和Fe2+/Fe3+氧化还原偶联的工作电压更高而引起了人们的广泛关注。这种阴极的主要障碍是在高电流速率下的电压滞后。本文报道了一种nasiconon型NaFe2-xInx(PO4)(MoO4)2 (NFIPM)阴极,该阴极表现出稳定的单相固溶反应,过电位明显减弱。铟策略性地加入到铁的位置,扩大晶格空间,以促进钠离子的扩散,也减少了NFIPM的能带隙。磁化率(M-T)和电子顺磁共振(EPR)测量表明,取代铟后,铁的自旋态增加。第一性原理计算也证实了掺杂铟后Na+迁移能垒的降低。优化后的NFIPM10在0.1 C下的比容量为111.85 mAh g−1,在2C下的循环稳定性高达800次。原位x射线衍射证实了NFIPM在(去)钠化过程中的可逆结构稳定性,强调了策略掺杂在增强钠离子存储中的作用。
期刊介绍:
Small serves as an exceptional platform for both experimental and theoretical studies in fundamental and applied interdisciplinary research at the nano- and microscale. The journal offers a compelling mix of peer-reviewed Research Articles, Reviews, Perspectives, and Comments.
With a remarkable 2022 Journal Impact Factor of 13.3 (Journal Citation Reports from Clarivate Analytics, 2023), Small remains among the top multidisciplinary journals, covering a wide range of topics at the interface of materials science, chemistry, physics, engineering, medicine, and biology.
Small's readership includes biochemists, biologists, biomedical scientists, chemists, engineers, information technologists, materials scientists, physicists, and theoreticians alike.