{"title":"了解锂化引起的体积变化及其对锂离子电池阴极多孔钴酸盐(LiCo2O4)的影响","authors":"L. Maake, B. Shibiri, P.E. Ngoepe, R.S. Ledwaba","doi":"10.1016/j.nxmate.2025.100601","DOIUrl":null,"url":null,"abstract":"<div><div>Spinel LiCo<sub>2</sub>O<sub>4</sub> exhibits superlative electrochemical performance due to its high Li<sup>+</sup> diffusion rate; meanwhile, porous nanomaterials offer large surface areas and pore volume, allowing materials to expand freely with lithiation. However, it is very difficult to synthesise LiCo<sub>2</sub>O<sub>4</sub> through conventional methods. As such, it has become redundant over the years. Therefore, herein, molecular dynamics simulation methods are employed to investigate the porosity and structural changes of three lithiated Li<sub>1+x</sub>Co<sub>2</sub>O<sub>4</sub> (0 ≤ x ≤ 1) nanoporous materials with cell dimensions of 67, 69, and 75 Å during the discharge process to improve their cycling performance and structural stability. The radial distribution functions showed structures, which have sufficiently amorphised and recrystallised with lithiation. Furthermore, the simulated XRDs showed peaks that correspond to the formation of the cobaltite LiCo<sub>2</sub>O<sub>4</sub> spinel when compared to experimental results. In addition, the XRDs also show significant peak shifts, splits, and broadening with increasing lithium concentration. This may be attributed to structural changes and phase transitions from cubic to tetragonal symmetry since multi-grained structures are observed at the Li<sub>1.75</sub>Co<sub>2</sub>O<sub>4</sub> concentration. Pore size changes in the materials are also observed with increasing lithium concentration, and the nanoporous materials experience some volume changes during the discharge process. Nanoporous 69 Å material is observed to have a great overall volume increase compared to its counterparts. However, all the nanoporous materials retain their structural integrity upon full lithiation at Li<sub>2.00</sub>Co<sub>2</sub>O<sub>4</sub>; indicating their potential to enhance the cycling performance and structural stability of LiCo<sub>2</sub>O<sub>4</sub> cathodes.</div></div>","PeriodicalId":100958,"journal":{"name":"Next Materials","volume":"8 ","pages":"Article 100601"},"PeriodicalIF":0.0000,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Understanding lithiation induced volume variations and its impact on porous cobaltite (LiCo2O4) for Li-ion battery cathodes\",\"authors\":\"L. Maake, B. Shibiri, P.E. Ngoepe, R.S. Ledwaba\",\"doi\":\"10.1016/j.nxmate.2025.100601\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Spinel LiCo<sub>2</sub>O<sub>4</sub> exhibits superlative electrochemical performance due to its high Li<sup>+</sup> diffusion rate; meanwhile, porous nanomaterials offer large surface areas and pore volume, allowing materials to expand freely with lithiation. However, it is very difficult to synthesise LiCo<sub>2</sub>O<sub>4</sub> through conventional methods. As such, it has become redundant over the years. Therefore, herein, molecular dynamics simulation methods are employed to investigate the porosity and structural changes of three lithiated Li<sub>1+x</sub>Co<sub>2</sub>O<sub>4</sub> (0 ≤ x ≤ 1) nanoporous materials with cell dimensions of 67, 69, and 75 Å during the discharge process to improve their cycling performance and structural stability. The radial distribution functions showed structures, which have sufficiently amorphised and recrystallised with lithiation. Furthermore, the simulated XRDs showed peaks that correspond to the formation of the cobaltite LiCo<sub>2</sub>O<sub>4</sub> spinel when compared to experimental results. In addition, the XRDs also show significant peak shifts, splits, and broadening with increasing lithium concentration. This may be attributed to structural changes and phase transitions from cubic to tetragonal symmetry since multi-grained structures are observed at the Li<sub>1.75</sub>Co<sub>2</sub>O<sub>4</sub> concentration. Pore size changes in the materials are also observed with increasing lithium concentration, and the nanoporous materials experience some volume changes during the discharge process. Nanoporous 69 Å material is observed to have a great overall volume increase compared to its counterparts. However, all the nanoporous materials retain their structural integrity upon full lithiation at Li<sub>2.00</sub>Co<sub>2</sub>O<sub>4</sub>; indicating their potential to enhance the cycling performance and structural stability of LiCo<sub>2</sub>O<sub>4</sub> cathodes.</div></div>\",\"PeriodicalId\":100958,\"journal\":{\"name\":\"Next Materials\",\"volume\":\"8 \",\"pages\":\"Article 100601\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2025-03-29\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Next Materials\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2949822825001194\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Next Materials","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2949822825001194","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
摘要
尖晶石钴酸锂因其较高的锂+扩散率而表现出卓越的电化学性能;同时,多孔纳米材料具有较大的表面积和孔隙率,可使材料在锂化过程中自由膨胀。然而,通过传统方法合成钴酸锂非常困难。因此,多年来它已变得多余。因此,本文采用分子动力学模拟方法研究了三种锂化 Li1+xCo2O4(0 ≤ x ≤ 1)纳米多孔材料在放电过程中的孔隙率和结构变化,这些材料的晶胞尺寸分别为 67、69 和 75 Å,以改善其循环性能和结构稳定性。径向分布函数显示,这些结构在锂化过程中充分非晶化和再结晶。此外,与实验结果相比,模拟 XRD 显示了与钴酸盐 LiCo2O4 尖晶石的形成相对应的峰值。此外,随着锂浓度的增加,XRD 还显示出明显的峰值偏移、分裂和展宽。这可能归因于结构变化和从立方对称到四方对称的相变,因为在锂浓度为 1.75Co2O4 时观察到了多晶粒结构。随着锂浓度的增加,材料中的孔径也发生了变化,纳米多孔材料在放电过程中经历了一些体积变化。与同类材料相比,69 Å 纳米多孔材料的整体体积增加很大。然而,所有纳米多孔材料在锂2.00Co2O4完全锂化时都保持了结构的完整性;这表明它们具有提高钴酸锂阴极的循环性能和结构稳定性的潜力。
Understanding lithiation induced volume variations and its impact on porous cobaltite (LiCo2O4) for Li-ion battery cathodes
Spinel LiCo2O4 exhibits superlative electrochemical performance due to its high Li+ diffusion rate; meanwhile, porous nanomaterials offer large surface areas and pore volume, allowing materials to expand freely with lithiation. However, it is very difficult to synthesise LiCo2O4 through conventional methods. As such, it has become redundant over the years. Therefore, herein, molecular dynamics simulation methods are employed to investigate the porosity and structural changes of three lithiated Li1+xCo2O4 (0 ≤ x ≤ 1) nanoporous materials with cell dimensions of 67, 69, and 75 Å during the discharge process to improve their cycling performance and structural stability. The radial distribution functions showed structures, which have sufficiently amorphised and recrystallised with lithiation. Furthermore, the simulated XRDs showed peaks that correspond to the formation of the cobaltite LiCo2O4 spinel when compared to experimental results. In addition, the XRDs also show significant peak shifts, splits, and broadening with increasing lithium concentration. This may be attributed to structural changes and phase transitions from cubic to tetragonal symmetry since multi-grained structures are observed at the Li1.75Co2O4 concentration. Pore size changes in the materials are also observed with increasing lithium concentration, and the nanoporous materials experience some volume changes during the discharge process. Nanoporous 69 Å material is observed to have a great overall volume increase compared to its counterparts. However, all the nanoporous materials retain their structural integrity upon full lithiation at Li2.00Co2O4; indicating their potential to enhance the cycling performance and structural stability of LiCo2O4 cathodes.