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.

Tatara, R., Yu, Y., Karayaylali, P., Chan, A., Zhang, Y., Jung, R., et al. (2019). Enhanced Cycling Performance of Ni-Rich Positive Electrodes (NMC) in Li-Ion Batteries by Reducing Electrolyte Free-Solvent Activity. ACS APPLIED MATERIALS & INTERFACES, 11(38), 34973-34988 [10.1021/acsami.9b11942].

Enhanced Cycling Performance of Ni-Rich Positive Electrodes (NMC) in Li-Ion Batteries by Reducing Electrolyte Free-Solvent Activity

Giordano L.;
2019

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.
Articolo in rivista - Articolo scientifico
Activity; Concentrated Electrolyte; Electrode-electrolyte Interface; Li-ion Batteries; Ni-rich Positive Electrodes; NMC; Solvation Structure;
English
34973
34988
16
Tatara, R., Yu, Y., Karayaylali, P., Chan, A., Zhang, Y., Jung, R., et al. (2019). Enhanced Cycling Performance of Ni-Rich Positive Electrodes (NMC) in Li-Ion Batteries by Reducing Electrolyte Free-Solvent Activity. ACS APPLIED MATERIALS & INTERFACES, 11(38), 34973-34988 [10.1021/acsami.9b11942].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/348613
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