Electrochemical characteristics of rancieite-type manganese oxide by mechanochemical synthesis

• Published in: Journal of power sources 2003-10, Vol.124 (1), p.174-181
• Main Authors: Woo, Sang-gil, Kim, Hansu, Lee, Churl Kyung, Sohn, Hun-Joon, Kang, Tak
• Format: Article
• Language: English
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Lithium-ion battery; Manganese oxide; Manganese oxide cathode; Mechanochemical synthesis; Rancieite; Soft X-ray absorption
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/S0378-7753(03)00619-0

Rancieite-type manganese oxide is synthesized by a mechanochemical method and its electrochemical characteristics as a cathode material for lithium secondary batteries are examined. The discharge capacity increases with milling time up to 45 h with a maximum of 274 mAh g −1. Further increase in milling time causes a decrease in capacity due to a phase transformation. Lithium insertion into the rancieite-type manganese cathode is composed of two processes, one between 2.0 and 4.0 V and the other between 1.5 and 2.0 V. The former is due to the reduction of Mn 4+ to Mn 3+, while the latter is due to the reduction of Mn 3+ to Mn 2+. These processes are identified by X-ray absorption spectra. The specific capacity of the rancieite-type manganese oxide shows good cycleability without transition to a spinel-like structure.