Guimei Han, Di Zhang, Da Zhang, Chunge Dang and Jianling Li
{"title":"Regulating π-type interactions between O 2p and TM t2g orbitals via Ti doping and surface dielectric coatings for Li-rich cathodes†","authors":"Guimei Han, Di Zhang, Da Zhang, Chunge Dang and Jianling Li","doi":"10.1039/D4QI02773F","DOIUrl":null,"url":null,"abstract":"<p >The irreversible anionic redox reaction and oxygen release of Li-rich layered oxide cathodes seriously hinder their commercial application. Here, a synergistic modification strategy of surface dielectric coating (TiNb<small><sub>2</sub></small>O<small><sub>7</sub></small>) and bulk phase Ti doping is proposed in this paper. TiNb<small><sub>2</sub></small>O<small><sub>7</sub></small>, as a dielectric oxide, can generate a reversed electric field during charging to block the migration path of anions inside the material. In addition, the unique three-dimensional Li<small><sup>+</sup></small> diffusion channels of TiNb<small><sub>2</sub></small>O<small><sub>7</sub></small> can improve the lithium-ion diffusion kinetics. The results show that the synergistic modification strategy fundamentally inhibits oxygen loss and enhances the reversibility of anion redox, while constructing a uniform and stable CEI interface. The co-modification strategy effectively improves the electrochemical performance of the materials. The modified sample can maintain a high capacity of 175.1 mA h g<small><sup>−1</sup></small> after 500 cycles at 1 C. This work provides new insights to improve the oxygen loss problem of Li-rich layered oxide cathodes.</p>","PeriodicalId":79,"journal":{"name":"Inorganic Chemistry Frontiers","volume":" 3","pages":" 1125-1138"},"PeriodicalIF":6.1000,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Inorganic Chemistry Frontiers","FirstCategoryId":"92","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2025/qi/d4qi02773f","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
The irreversible anionic redox reaction and oxygen release of Li-rich layered oxide cathodes seriously hinder their commercial application. Here, a synergistic modification strategy of surface dielectric coating (TiNb2O7) and bulk phase Ti doping is proposed in this paper. TiNb2O7, as a dielectric oxide, can generate a reversed electric field during charging to block the migration path of anions inside the material. In addition, the unique three-dimensional Li+ diffusion channels of TiNb2O7 can improve the lithium-ion diffusion kinetics. The results show that the synergistic modification strategy fundamentally inhibits oxygen loss and enhances the reversibility of anion redox, while constructing a uniform and stable CEI interface. The co-modification strategy effectively improves the electrochemical performance of the materials. The modified sample can maintain a high capacity of 175.1 mA h g−1 after 500 cycles at 1 C. This work provides new insights to improve the oxygen loss problem of Li-rich layered oxide cathodes.
富锂层状氧化物阴极的不可逆阴离子氧化还原反应和氧释放严重阻碍了其商业化应用。本文提出了一种表面介质涂层(TiNb2O7)和体相Ti掺杂的协同改性策略。TiNb2O7作为介电氧化物,在充电过程中会产生反向电场,阻断材料内部阴离子的迁移路径。此外,TiNb2O7独特的三维Li+扩散通道可以改善锂离子的扩散动力学。体相Ti掺杂可以增加氧释放反应的能垒,而较强的Ti- o键可以调节过渡金属的电子结构和π杂化,从而稳定氧骨架。XPS、CV和HRTEM结果表明,协同修饰策略从根本上抑制了氧损失,增强了阴离子氧化还原的可逆性,同时构建了均匀稳定的CEI界面。共改性策略有效地提高了材料的电化学性能。在1C下循环500次后,改性后的样品可以保持175.1 mAh g-1的高容量。这项工作为改善富锂层状氧化物阴极的氧损失问题提供了新的见解。