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Kinetics and Stability of Li-Ion Transfer at the LiCoO2 (104) Plane and Electrolyte Interface.
- Source :
- Journal of The Electrochemical Society; 11/1/2018, Vol. 165 Issue 14, pA3221-A3229, 9p
- Publication Year :
- 2018
-
Abstract
- Surface-coated/uncoated epitaxial LiCoO<subscript>2</subscript> film electrodes with (104) orientations were fabricated on SrRuO<subscript>3</subscript>(100)/Nb:SrTiO<subscript>3</subscript>(100) using pulsed laser deposition. Films with thicknesses of ∼18 nm and flat surfaces with roughnesses of less than 1 nm were model systems for clarifying the kinetics of Li-ion transfer at the electrode/electrolyte interface. The Li-ion transfer characteristics at the interface between the LiCoO<subscript>2</subscript> electrode and the electrolyte (LiPF6, ethylene carbonate + diethyl carbonate) were investigated by electrochemical impedance spectrometry. The charge-transfer resistance (R<subscript>ct</subscript>) of uncoated LiCoO<subscript>2</subscript> increased from the early cycles when charged/discharged at 3.0-4.2 V. When charged/discharged at 3.0-4.5 V, the R<subscript>ct</subscript> of the uncoated LiCoO<subscript>2</subscript> rapidly increased from the first charge. In contrast, the R<subscript>ct</subscript> of Li2ZrO<subscript>3</subscript>-coated LiCoO<subscript>2</subscript> remained almost constant during the early cycles when charged/discharged either at 3.0-4.2 or at 3.0-4.5 V. The interfacial resistances of the coated and uncoated LiCoO<subscript>2</subscript> electrodes were almost equal (~100 Ω cm<superscript>2</superscript>). The activation energy for charge transfer was lower for the coated LiCoO<subscript>2</subscript> electrode compared to that for the uncoated electrode. The current-rate capability was significantly improved by surface coating even at high-voltage charge/discharge at 3.0-4.5 V. The charge transfer process is the rate-determining step of the charge/discharge reaction. [ABSTRACT FROM AUTHOR]
- Subjects :
- ELECTRODES
THIN films
PULSED laser deposition
Subjects
Details
- Language :
- English
- ISSN :
- 00134651
- Volume :
- 165
- Issue :
- 14
- Database :
- Supplemental Index
- Journal :
- Journal of The Electrochemical Society
- Publication Type :
- Academic Journal
- Accession number :
- 133394717
- Full Text :
- https://doi.org/10.1149/2.0151814jes