Mechanical Damage of Surface Films and Failure of Nano-Sized Silicon Electrodes in Lithium Ion Batteries
| Autor: | Hosang Park, Jae Gil Lee, Eun Kyung Kim, Jongjung Kim, Seung M. Oh, Hyun-seung Kim, Jeong Beom Lee, Dong Sub Jung, Ji Heon Ryu |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
Silicon Passivation Renewable Energy Sustainability and the Environment 020209 energy Inorganic chemistry Diethyl carbonate chemistry.chemical_element 02 engineering and technology Electrolyte 021001 nanoscience & nanotechnology Condensed Matter Physics Surfaces Coatings and Films Electronic Optical and Magnetic Materials chemistry.chemical_compound Chemical engineering chemistry 0202 electrical engineering electronic engineering information engineering Materials Chemistry Electrochemistry Lithium 0210 nano-technology Deposition (law) Ethylene carbonate Faraday efficiency |
| Zdroj: | Journal of The Electrochemical Society. 164:A6103-A6109 |
| ISSN: | 1945-7111 0013-4651 |
| DOI: | 10.1149/2.0141701jes |
| Popis: | This work demonstrates that the mechanical damage of surface passivation films plays an underlying role in the failure of nano-sized Si electrodes in lithium-ion batteries. The surface film derived from the standard electrolyte (1.3 M LiPF6 dissolved in ethylene carbonate/diethyl carbonate) during the first lithiation step is damaged by the mechanical stress caused by the volume contraction of Si particles during the subsequent de-lithiation period. The electrolyte decomposes on the newly exposed Si surface and film deposition occurs, which is then mechanically damaged again owing to volume change of the Si particles. Such film deposition/damage cycles are repeated until the mechanical stress becomes insignificant as a result of capacity decay. Continued electrolyte decomposition, which prevails in the early cycling period, produces electronically insulating films located between Si particles, which cause Li trapping within the Si matrix. Li trapping is found to be responsible for the rapid decrease in capacity and Coulombic efficiency in the intermediate period of cycling. When fluoroethylene carbonate (FEC) is added to the electrolyte, a surface film that is robust against mechanical stress is produced. As a result, the FEC-derived surface film maintains its passivating ability and suppresses the irreversible reactions, resulting in a better cycling performance. |
| Databáze: | OpenAIRE |
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