{"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.