A Comprehensive Study of Manganese Deposition and Side Reactions in Li-Ion Battery Electrodes
A thorough investigation of both manganese (Mn) deposition onto graphite and its side reactions was conducted based on complementary techniques including CV, EIS, GCPL, ICP-OES, SEM and EDS. Each measurement revealed a specific aspect of the degradation phenomena, which taken together all pointed in a common direction. This study focused on 1) deposition mechanisms and effects of manganese ions on the SEI layer; 2) the effects of manganese deposition on electrochemical performance; and 3) direct observation of decomposed layers induced by manganese deposition. It was confirmed that adding Mn(PF6)2 salt in the electrolyte results in severe capacity decrease and impedance rise. It is found that manganese ions in the electrolyte participate to generate Mn-containing SEI layers when depositing onto the graphite surface accompanied by additional side reactions. Interestingly, before manganese ions deposit onto the graphite electrode, they enhance cell capacity due to additional oxidation reactions. It is found that the reaction of manganese ions changes with the voltage conditions during charge or discharge and the lithiation status of the graphite electrode.
Y. K. Lee et al., "A Comprehensive Study of Manganese Deposition and Side Reactions in Li-Ion Battery Electrodes," Journal of the Electrochemical Society, vol. 164, no. 12, pp. A2812-A2822, Electrochemical Society Inc., Sep 2017.
The definitive version is available at https://doi.org/10.1149/2.1851712jes
Mechanical and Aerospace Engineering
Intelligent Systems Center
Keywords and Phrases
Deposition; Electric batteries; Electric discharges; Electrodes; Electrolytes; Graphite; Graphite electrodes; Ions; Lithium-ion batteries; Manganese compounds; Secondary batteries, Complementary techniques; Decomposed layers; Deposition mechanism; Direct observations; Electrochemical performance; Li-ion battery electrodes; Oxidation reactions; Voltage conditions, Manganese
International Standard Serial Number (ISSN)
Article - Journal
© 2017 Electrochemical Society Inc., All rights reserved.
01 Sep 2017