Understanding Electrolyte Decomposition of Graphite/NCM811 Cells at Elevated Operating Voltage
| Autor: | Hubert A. Gasteiger, Brett L. Lucht, Nina Laszczynski, Sophie Solchenbach |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Renewable Energy Sustainability and the Environment 020209 energy Gas evolution reaction Analytical chemistry 02 engineering and technology Electrolyte Condensed Matter Physics Electrochemistry Cathode Surfaces Coatings and Films Electronic Optical and Magnetic Materials Anode Dielectric spectroscopy law.invention ddc law 0202 electrical engineering electronic engineering information engineering Materials Chemistry Graphite Inductively coupled plasma |
| Popis: | Cells containing LiNixCoyMn1-x-yO2 (NCM) materials with very high nickel content suffer from cathode material degradation upon cycling, especially when operating these cells at higher voltage. While the cathode particle degradation is a problem other issues contribute to electrochemical performance loss. Graphite/LiNi0.8Co0.1Mn0.1O2 cells have been cycled to different upper cutoff voltages and investigated with electrochemical impedance spectroscopy (EIS), gas analysis with online electrochemical mass spectroscopy (OEMS), nuclear magnetic resonance (NMR) spectroscopy, gas chromatography with MS (GCMS) and inductively coupled plasma MS (ICP-MS). Increased gas evolution was observed when the upper cutoff voltage was increased from 4.2 to 4.6 V. An increase in O2 evolution upon cycling as well as an increase of CO2 upon increasing the voltage, have been observed. More electrolyte decomposition products are observed on the anode for cells cycled to higher voltage. An increased amount of nickel has been detected on the graphite electrode in accordance with an increased reaction of the cathode surface with the electrolyte leading to transition metal dissolution. Finally, an increase in carbonate solvent transesterification products has been observed. |
| Databáze: | OpenAIRE |
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