{"title":"Revealing proton-coupled exchange mechanism in aqueous ion-exchange synthesis of nickel-rich layered cathodes for lithium-ion batteries","authors":"","doi":"10.1016/j.esci.2024.100229","DOIUrl":null,"url":null,"abstract":"<div><p>Ion exchange is a promising synthetic method for alleviating severe cation mixing in traditional layered oxide materials for lithium-ion batteries, leading to enhanced structural stability. However, the underlying mechanisms of ion exchange are still not fully understood. Such a fundamental study of the ion-exchange mechanism is needed for achieving the controllable synthesis of layered oxides with a stable structure. Herein, we thoroughly unearth the underlying mechanism that triggers the ion exchange of Ni-rich materials in aqueous solutions by examining time-resolved structural evolution combined with theoretical calculations. Our results reveal that the reaction pathway of ion exchange can be divided into two steps: protonation and lithiation. The proton is the key to achieving charge balance in the ion exchange process, as revealed by X-ray adsorption spectroscopy and inductive coupled plasma analysis. In addition, the intermediate product shows high lattice distortion during ion exchange, but it ends up with a most stable product with high lattice energy. Such apparent discrepancies in lattice energy between materials before and after ion exchange emphasize the importance of synthetic design in structural stability. This work provides new insights into the ion-exchange synthesis of Ni-rich oxide materials, which advances the development of cathode materials for high-performance lithium-ion batteries.</p></div>","PeriodicalId":100489,"journal":{"name":"eScience","volume":"4 4","pages":"Article 100229"},"PeriodicalIF":42.9000,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2667141724000028/pdfft?md5=6879aa6f1f85e2c42b209cc154ebad09&pid=1-s2.0-S2667141724000028-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"eScience","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2667141724000028","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ELECTROCHEMISTRY","Score":null,"Total":0}
引用次数: 0
Abstract
Ion exchange is a promising synthetic method for alleviating severe cation mixing in traditional layered oxide materials for lithium-ion batteries, leading to enhanced structural stability. However, the underlying mechanisms of ion exchange are still not fully understood. Such a fundamental study of the ion-exchange mechanism is needed for achieving the controllable synthesis of layered oxides with a stable structure. Herein, we thoroughly unearth the underlying mechanism that triggers the ion exchange of Ni-rich materials in aqueous solutions by examining time-resolved structural evolution combined with theoretical calculations. Our results reveal that the reaction pathway of ion exchange can be divided into two steps: protonation and lithiation. The proton is the key to achieving charge balance in the ion exchange process, as revealed by X-ray adsorption spectroscopy and inductive coupled plasma analysis. In addition, the intermediate product shows high lattice distortion during ion exchange, but it ends up with a most stable product with high lattice energy. Such apparent discrepancies in lattice energy between materials before and after ion exchange emphasize the importance of synthetic design in structural stability. This work provides new insights into the ion-exchange synthesis of Ni-rich oxide materials, which advances the development of cathode materials for high-performance lithium-ion batteries.
离子交换是一种很有前途的合成方法,它可以缓解传统锂离子电池层状氧化物材料中严重的阳离子混合现象,从而提高结构的稳定性。然而,人们对离子交换的基本机制仍不完全了解。要实现结构稳定的层状氧化物的可控合成,就需要对离子交换机制进行基础研究。在此,我们通过研究时间分辨结构演化并结合理论计算,彻底揭示了富镍材料在水溶液中引发离子交换的内在机制。我们的研究结果表明,离子交换的反应途径可分为两个步骤:质子化和锂化。质子是离子交换过程中实现电荷平衡的关键,这一点通过 X 射线吸附光谱和感应耦合等离子体分析得以揭示。此外,中间产物在离子交换过程中显示出较高的晶格畸变,但最终得到的却是晶格能较高的最稳定产物。离子交换前后材料晶格能的这种明显差异强调了合成设计对结构稳定性的重要性。这项研究为富镍氧化物材料的离子交换合成提供了新的见解,推动了高性能锂离子电池正极材料的发展。