Understanding atomic scale phenomena within the surface layer of a long-term cycled 5 V spinel electrode. (January 2016)

• Record Type: Journal Article
• Authors: Vissers, Daniel R.; Isheim, Dieter; Zhan, Chun; Chen, Zonghai; Lu, Jun; Amine, Khalil
• Is Part Of: Nano energy. Volume 19(2016:Jan.)
• Page Start: 297
• Page End: 306
• Publication Date: 2016-01
• Subjects: Atom probe tomography -- 5 V spinel -- Scanning transmission electron microscopy; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2015.11.031
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Lithium-ion batteries utilizing 5 V spinel material, Li x Mn1.5 Ni0.5 O4 have received considerable interest in recent years for their ability to deliver high energy and power densities. In this paper, we report an atomic scale analysis of the surface layer of a core–shell 5 V spinel structure where a small amount of the manganese lattice sites have been substituted with cobalt in the shell to reach a stoichiometry of Li x Mn1.18 Ni0.55 Co0.27 O4 . Our analyses include electrochemical analysis, atom probe tomography (APT) analysis, kinetic analysis of the interfacial reactions, and high resolution scanning transmission electron microscopy (HR-TEM) analysis. The APT analysis is performed on the material before and after long-term cycling at room temperature to provide insights into the atomic scale phenomena within the surface layer of the electrode material. Our APT data reveals a 25–30 nano-meter (nm) region which forms after cycling. From our analyses, we believe that the outer few nanometers of this region stabilizes the 5 V spinel within the chemical environment of the lithium-ion cell such that its structure is not compromised and thereby enables this material to cycle without significant capacity fading. Graphical abstract: Understanding atomic scale phenomena within the surface layer of a long-term cycled 5 V spinel electrode: the use of atom probe tomography analysis, standard electrochemical analysis, kinetic analysis of the interfacial reactions, and high resolution scanning transmission electron microscopy analysis reveals new insights into the phenomena which occur in the surface layer of a cycled core–shell 5 V spinel. Highlights: Electrochemical analysis of 5 V spinel with cobalt in the outer most layer. Atom probe tomography analysis of uncycled and cycled 5 V spinel with cobalt in the outer most layer. Kinetic analysis of the interfacial reaction. HR-STEM of cycled 5 V spinel with cobalt in the outer most layer.