Enhanced Cycling Performance of Ni-Rich Positive Electrodes (NMC) in Li-Ion Batteries by Reducing Electrolyte Free-Solvent Activity
Author(s)
Tatara, Ryoichi; Yu, Yang; Karayaylali, Pinar; Chan, Averey K.; Zhang, Yirui; Jung, Roland; Maglia, Filippo; Giordano, Livia; Shao-Horn, Yang; ... Show more Show less
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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.
Date issued
2019-08Department
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 EngineeringJournal
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
ISSN
1944-8244
1944-8252