{"title":"Nickel Regulating Endows Fe7Se8 With Stable Potassium-Ion Storage","authors":"Qingyi Zhao, Fangrui Yu, Yizhi Yuan, Song Chen, Wei Chen, Hongli Deng, Xiangdong Guo, Hongtao Sun, Hao Chen, Jian Zhu","doi":"10.1002/cnl2.70007","DOIUrl":null,"url":null,"abstract":"<p>Iron-based selenides are considered as potential electrode materials in potassium-ion batteries (PIBs) owing to the merits of high capacity, intrinsic safety, and cost-effectiveness. However, sluggish electronic/ionic transport kinetics and large volume variations result in suboptimal electrochemical performance. Herein, we report a nickel-doped Fe<sub>7</sub>Se<sub>8</sub> with double-shell N-doped carbon (Ni-Fe<sub>7</sub>Se<sub>8</sub>@DNC) as anode for robust potassium ion storage. Notably, the introduction of Ni induces the lattice distortion and leads to a rearrangement of charge, thereby creating numerous active sites and optimizing the band structure to enhance charge transport. Additionally, the elastic carbon shell can synergistically mitigate the volume expansion upon cycling and maintain the structural stability. Thus, the Ni-Fe<sub>7</sub>Se<sub>8</sub>@DNC presented excellent cycling stability of more than 1 year (464.8 mAh g<sup>−1</sup>after 1000 cycles at 0.1 A g<sup>−1</sup>, the best stability among all iron-based selenides) and satisfactory rate capability. The potassium-ion hybrid capacitors (PIHCs) have also demonstrated a remarkable energy density of 186.5 Wh kg<sup>−1</sup> at 0.2 A g<sup>−1</sup>. Density functional theory calculations, in conjunction with a range of characterization methods, validate the rapid pseudocapacitive effect and lower ion diffusion energy barriers, resulting from Ni doping, improve reaction kinetics. This study paves the avenue for novel anode material designs for PIBs.</p>","PeriodicalId":100214,"journal":{"name":"Carbon Neutralization","volume":"4 2","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cnl2.70007","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Carbon Neutralization","FirstCategoryId":"1085","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/cnl2.70007","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Iron-based selenides are considered as potential electrode materials in potassium-ion batteries (PIBs) owing to the merits of high capacity, intrinsic safety, and cost-effectiveness. However, sluggish electronic/ionic transport kinetics and large volume variations result in suboptimal electrochemical performance. Herein, we report a nickel-doped Fe7Se8 with double-shell N-doped carbon (Ni-Fe7Se8@DNC) as anode for robust potassium ion storage. Notably, the introduction of Ni induces the lattice distortion and leads to a rearrangement of charge, thereby creating numerous active sites and optimizing the band structure to enhance charge transport. Additionally, the elastic carbon shell can synergistically mitigate the volume expansion upon cycling and maintain the structural stability. Thus, the Ni-Fe7Se8@DNC presented excellent cycling stability of more than 1 year (464.8 mAh g−1after 1000 cycles at 0.1 A g−1, the best stability among all iron-based selenides) and satisfactory rate capability. The potassium-ion hybrid capacitors (PIHCs) have also demonstrated a remarkable energy density of 186.5 Wh kg−1 at 0.2 A g−1. Density functional theory calculations, in conjunction with a range of characterization methods, validate the rapid pseudocapacitive effect and lower ion diffusion energy barriers, resulting from Ni doping, improve reaction kinetics. This study paves the avenue for novel anode material designs for PIBs.
铁基硒化物具有高容量、固有安全性和成本效益等优点,被认为是钾离子电池极具潜力的电极材料。然而,缓慢的电子/离子传递动力学和大的体积变化导致电化学性能不理想。在这里,我们报道了一种掺杂镍的Fe7Se8与双壳氮掺杂碳(Ni-Fe7Se8@DNC)作为稳健的钾离子存储阳极。值得注意的是,Ni的引入引起晶格畸变并导致电荷重排,从而产生大量活性位点并优化能带结构以增强电荷输运。此外,弹性碳壳可以协同减缓循环时的体积膨胀,保持结构的稳定性。因此,Ni-Fe7Se8@DNC具有良好的循环稳定性,在0.1 A g−1下循环1000次后可达到464.8 mAh g−1,是所有铁基硒化物中稳定性最好的)和令人满意的倍率能力。钾离子混合电容器(pihc)在0.2 a g−1时也表现出了186.5 Wh kg−1的显著能量密度。密度泛函理论计算,结合一系列表征方法,验证了镍掺杂导致的快速赝电容效应和较低的离子扩散能垒,改善了反应动力学。本研究为新型阳极材料的设计铺平了道路。