Enhanced Cycling Performance of Ni-Rich Positive Electrodes (NMC) in Li-Ion Batteries by Reducing Electrolyte Free-Solvent Activity
Name
Enhanced Cycling Performance of Ni-rich Positive Electrodes (NMC) in Li-ion Batteries by Reducing Electrolyte Free-solvent Activity.pdf
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11.34 MB
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Author(s)
Tatara, Ryoichi
Yu, Yang
Karayaylali, Pinar
Chan, Averey K.
Zhang, Yirui
Jung, Roland
Maglia, Filippo
Giordano, Livia
Shao-Horn, Yang
Date Issued
August 2019
Journal
ACS Applied Materials and Interfaces
Publisher
American Chemical Society (ACS)
Citation
Tatara, Ryoichi et al. "Enhanced Cycling Performance of Ni-Rich Positive Electrodes (NMC) in Li-Ion Batteries by Reducing Electrolyte Free-Solvent Activity." ACS Applied Materials and Interfaces 11, 38 (July 2019): 34973–34988 © 2019 American Chemical Society
Version
Author's final manuscript
Abstract
The interfacial (electro)chemical reactions between electrode and electrolyte dictate the cycling stability of Li-ion batteries. Previous experimental and computational results have shown that replacing Mn and Co with Ni in layered LiNixMnyCo1–x–yO2 (NMC) positive electrodes promotes the dehydrogenation of carbonate-based electrolytes on the oxide surface, which generates protic species to decompose LiPF6 in the electrolyte. In this study, we utilized this understanding to stabilize LiNi0.8Mn0.1Co0.1O2 (NMC811) by decreasing free-solvent activity in the electrolyte through controlling salt concentration and salt dissociativity. Infrared spectroscopy revealed that highly concentrated electrolytes with low free-solvent activity had no dehydrogenation of ethylene carbonate, which could be attributed to slow kinetics of dissociative adsorption of Li+-coordinated solvents on oxide surfaces. The increased stability of the concentrated electrolyte against solvent dehydrogenation gave rise to high capacity retention of NMC811 with capacities greater than 150 mA h g–1 (77% retention) after 500 cycles without oxide-coating and Ni-concentration gradients or electrolyte additives.
MIT Department
Massachusetts Institute of Technology. Research Laboratory of Electronics
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1021/acsami.9b11942
