Mn(II) deposition on anodes and its effects on capacity fade in spinel lithium manganate–carbon systems

• Published in: Nature communications Vol. 4; no. 1; p. 2437
• Main Authors: Zhan, Chun, Lu, Jun, Jeremy Kropf, A., Wu, Tianpin, Jansen, Andrew N., Sun, Yang-Kook, Qiu, Xinping, Amine, Khalil
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 30.09.2013; Nature Publishing Group
• Subjects: 639/301/299/891; 639/638/161; Batteries; Carbon; Electrolytes; Electrons; Graphite; Humanities and Social Sciences; Lithium; multidisciplinary; Oxidation; Science; Science (multidisciplinary); United States > US
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms3437

Dissolution and migration of manganese from cathode lead to severe capacity fading of lithium manganate–carbon cells. Overcoming this major problem requires a better understanding of the mechanisms of manganese dissolution, migration and deposition. Here we apply a variety of advanced analytical methods to study lithium manganate cathodes that are cycled with different anodes. We show that the oxidation state of manganese deposited on the anodes is +2, which differs from the results reported earlier. Our results also indicate that a metathesis reaction between Mn(II) and some species on the solid–electrolyte interphase takes place during the deposition of Mn(II) on the anodes, rather than a reduction reaction that leads to the formation of metallic Mn, as speculated in earlier studies. The concentration of Mn deposited on the anode gradually increases with cycles; this trend is well correlated with the anodes rising impedance and capacity fading of the cell. Lithium manganate is an important cathode material for lithium-ion batteries; however, its capacity-fading mechanism is unclear. Zhan et al . identify the oxidation state of manganese deposited on the anode, which leads to an irreversible rising in anode resistance and consequently a shortened battery life.