In SituStructural Study of 4V-Range Lithium Extraction/Insertion in Fluorine-Substituted LiMn2O4

✍ Scribed by M.R. Palacı́n; F. Le Cras; L. Seguin; M. Anne; Y. Chabre; J.M. Tarascon; G. Amatucci; G. Vaughan; P. Strobel

• Book ID: 102608013
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 327 KB
• Volume: 144
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8166

✦ Synopsis

The structural features accompanying the lithium extraction/insertion process in a 6uorine-substituted spinel oxide with formula LiMn 2 (O 3.74 F 0.26 ) were studied in situ using Bellcoretype plastic batteries directly placed in a synchrotron X-ray beam. The initial material contains two phases, a cubic spinel and a slightly orthorhombically distorted one (major phase). It becomes entirely cubic on extraction of 0.17 Li atoms per formula unit. The lithium extraction reaction around 4 V vs Li/Li ؉ can be divided into three regions as a function of lithium content x: (1) a single-phase range for 0.594x40.83, (2) a two-phase range for 0.234x40.59 with equilibrium potential 4.122 V, (3) a narrow single-phase range III for 0.184x40.23. These three domains are fully reversible. With the exception of the presence of the initial orthorhombic distortion, the main features of the so-called electrochemical 4 V plateau are very similar to those of stoichiometric Li x Mn 2 O 4 .