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富锂3d和4d阴极中氧氧化还原的纳米结构转变
作者:小柯机器人 发布时间:2021/4/11 14:07:34

美国石溪大学的Karena W. Chapman小组发现,纳米结构转变是富锂3d和4d阴极中氧氧化还原的标志。 这一研究成果发表在2021年4月7日出版的国际学术期刊《美国化学会杂志》上。

聚焦LRNMC阴极,该课题组发现使用小角X射线散射(SAXS)和operando X射线衍射(XRD),在阴极内形成了低电子密度的纳米级畴作为O氧化的结构结果。在小角度散射区观察到的特征表明,纳米孔的形成首先出现在O氧化过程中,并且部分可逆。

这种特性在传统的正极材料中并不存在,包括化学计量NMC和锂镍钴铝氧化物(NCA),但在这里测试的其他富锂系统,如Li2RuO3和Li1.3Nb0.3Mn0.4O2中似乎很常见。

据悉,富锂的镍锰钴氧化物(LRNMC)由于其更高的、初始已获得的储能能力,正在被用作化学计量的镍锰钴氧化物(NMC)阴极材料的替代品。这种较高的容量与可逆的O氧化有关。然而,周围的阴极结构适应O化学变化的机制仍然不完整,这使得设计策略来缓解因延长循环而导致的不良电极性能成为挑战。

附:英文原文

Title: Nanostructure Transformation as a Signature of Oxygen Redox in Li-Rich 3d and 4d Cathodes

Author: Antonin Grenier, Gabrielle E. Kamm, Yixuan Li, Hyeseung Chung, Ying Shirley Meng, Karena W. Chapman

Issue&Volume: April 7, 2021

Abstract: Lithium-rich nickel manganese cobalt oxide (LRNMC) is being explored as an alternative to stoichiometric nickel manganese cobalt oxide (NMC) cathode materials due to its higher, initially accessible, energy-storage capacity. This higher capacity has been associated with reversible O oxidation; however, the mechanism through which the change in O chemistry is accommodated by the surrounding cathode structure remains incomplete, making it challenging to design strategies to mitigate poor electrode performance resulting from extended cycling. Focusing on LRNMC cathodes, we identify nanoscale domains of lower electron density within the cathode as a structural consequence of O oxidation using small-angle X-ray scattering (SAXS) and operando X-ray diffraction (XRD). A feature observed in the small angle scattering region suggests the formation of nanopores, which first appears during O oxidation, and is partially reversible. This feature is not present in traditional cathode materials, including stoichiometric NMC and lithium nickel cobalt aluminum oxide (NCA) but appears to be common to other Li-rich systems tested here, Li2RuO3 and Li1.3Nb0.3Mn0.4O2.

DOI: 10.1021/jacs.1c00497

Source: https://pubs.acs.org/doi/10.1021/jacs.1c00497

 

期刊信息

JACS:《美国化学会志》,创刊于1879年。隶属于美国化学会,最新IF:14.612
官方网址:https://pubs.acs.org/journal/jacsat
投稿链接:https://acsparagonplus.acs.org/psweb/loginForm?code=1000