Novel Synthesis Process and Structural Characterization of Li–Mn–O Spinels

✍ Scribed by Toshimi Takada; Hirotoshi Enoki; Hiroshi Hayakawa; Etsuo Akiba

• Book ID: 102974839
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 643 KB
• Volume: 139
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1998.7843

✦ Synopsis

A new process for the synthesis of well-crystallized lithium manganese spinels with a homogenous composition Li 1؉x Mn 2؊x O 4 (04x40.333) has been developed using the stoichiometry mixture of lithium acetate LiOAc and manganese nitrate Mn(NO 3 ) 2 as starting materials. The decomposition of the raw materials and the stoichiometry mixture was studied using TG-DTA; the formation of lithium manganospinels occurs below 400°C. The crystallites appear to be single crystals in SEM micrographs. The size of the crystallites was in the range of 0.1 to 2.0 m and depended on the synthesis conditions. The crystal structure of these compounds was studied using X-ray powder diffraction and Rietveld refinement. The lattice parameter and manganese occupancy at 16d sites in the space group Fd3 m are sensitive to both the synthesis temperature and the composition of the spinels (Li/Mn ratio) as a result of the variation in manganese valency. Synthesis temperature, atmosphere, and the Li/Mn ratio in the starting materials are the key issues for control of the manganese valency in spinel Li 1؉x Mn 2؊x O 4 (04x40.333) for use in rechargeable lithium batteries.