{"title":"Surface reconstructed layer with bulk high-valence Mo doping to achieve long-life LiMn2O4 cathode material","authors":"","doi":"10.1016/j.electacta.2024.144706","DOIUrl":null,"url":null,"abstract":"<div><p>Mo doping plays a striking role in the stability enhancement of LiMn<sub>2</sub>O<sub>4</sub> cathode materials. However, the underlying microscopic mechanism is still unclear. Here, we elucidate that the relationship between the atomic position of Mo doping in LiMn<sub>2</sub>O<sub>4</sub> and the stability enhancement of Mo-doped LiMn<sub>2</sub>O<sub>4</sub> by utilizing the spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM). It exhibits that the part of Mo<sup>6+</sup> ions occupy empty Mn 16c site to form a surface reconstructed layer of rock-salt like phase on the outermost surface and other Mo<sup>6+</sup> ions dope into the Mn octahedral 16d sites to form LiMo<sub>x</sub>Mn<sub>2-x</sub>O<sub>4</sub> in bulk, which is beneficial for inhibiting the parasitic side reactions. Concomitantly, this dual modification of bulk structure and surface can significantly enhance electrode reversibility and Li<sup>+</sup> diffusion. As a result, excellent long cycling stability of the as-designed optimal LiMo<sub>0.01</sub>Mn<sub>1.99</sub>O<sub>4</sub> after 1500 cycles with 61.61 % capacity retention at 10 C (1 C = 148 mAh <em>g</em><sup>−1</sup>) is presented, with an initial discharge capacity of 88.30 mAh <em>g</em><sup>−1</sup>. Our research provides a clever approach for regulating the surface structure/bulk architecture in LiMn<sub>2</sub>O<sub>4</sub> cathode materials.</p></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":null,"pages":null},"PeriodicalIF":5.5000,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Electrochimica Acta","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0013468624009460","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ELECTROCHEMISTRY","Score":null,"Total":0}
引用次数: 0
Abstract
Mo doping plays a striking role in the stability enhancement of LiMn2O4 cathode materials. However, the underlying microscopic mechanism is still unclear. Here, we elucidate that the relationship between the atomic position of Mo doping in LiMn2O4 and the stability enhancement of Mo-doped LiMn2O4 by utilizing the spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM). It exhibits that the part of Mo6+ ions occupy empty Mn 16c site to form a surface reconstructed layer of rock-salt like phase on the outermost surface and other Mo6+ ions dope into the Mn octahedral 16d sites to form LiMoxMn2-xO4 in bulk, which is beneficial for inhibiting the parasitic side reactions. Concomitantly, this dual modification of bulk structure and surface can significantly enhance electrode reversibility and Li+ diffusion. As a result, excellent long cycling stability of the as-designed optimal LiMo0.01Mn1.99O4 after 1500 cycles with 61.61 % capacity retention at 10 C (1 C = 148 mAh g−1) is presented, with an initial discharge capacity of 88.30 mAh g−1. Our research provides a clever approach for regulating the surface structure/bulk architecture in LiMn2O4 cathode materials.
期刊介绍:
Electrochimica Acta is an international journal. It is intended for the publication of both original work and reviews in the field of electrochemistry. Electrochemistry should be interpreted to mean any of the research fields covered by the Divisions of the International Society of Electrochemistry listed below, as well as emerging scientific domains covered by ISE New Topics Committee.