123rd General Meeting of the KCS

Type Oral Presentation
Area Oral Presentation of Young Scholars in Electrochemistry
Room No. Room 407+408
Time THU 10:30-11:00
Code ELEC.O-10
Subject Degradation Mechanisms in Lithium-Ion Batteries with Layered Transition Metal Oxide Based Cathode Active Materials
Authors A.T.S. Freiberg, H.A. Gasteiger*, R. Jung, M. Metzger, S. Solchenbach, B. Strehle, T. Teufl, J. Wandt
Technical Electrochemistry, Dept. of Chemistry and Catalysis Research Center, Germany
Abstract Promising cathode active materials (CAMs) to increase the energy density of lithium ion batteries are nickel-rich NCM (LiNixCoyMnxO2 with x+y+z=1) and overlithiated so-called HE NCM (Li1+xM1-xO2; with M=Ni, Co, Mn) 1, 2. However, at high states-of-charge (SOC), molecular oxygen is released from the surface of these materials, not only leading to a growth of the cathode impedance, but also to enhanced electrolyte oxidation 3,4. Based on these observations, we suggested that the overall oxidation of the electrolyte can be distinguished into a chemical oxidation mechanism triggered by the release of active oxygen at high SOC and into a purely electrochemical oxidation mechanism initiating at high potentials 5.

Using on-line electrochemical mass spectrometry (OEMS) 3-5 and operando emission spectroscopy, we will provide evidence that the chemical electrolyte oxidation mechanism is triggered by the release of singlet oxygen from NCM and HE NCM surfaces at high SOC. It will be discussed how the reaction of singlet oxygen with the electrolyte solvents can result in the formation of protic species 6, leading to transition metal dissolution from the CAMs 7. As dissolved transition metals will deposit on the lithium-ion battery anode, the effect of transition metals on the stability of the graphite SEI will also be discussed 8.

References:
1. D. Andre, S.-J. Kim, P. Lamp, S.F. Lux, F. Maglia, O. Paschos, B. Stiaszny, J. Mater. Chem. A 3 (2015), 6709.
2. K.G. Gallagher, S. Goebel, T. Greszler, M. Mathias, W. Oelerich, D. Eroglu, V. Srinivasan, Energy Environ. Sci. 7 (2014) 1555.
3. B. Strehle, K. Kleiner, R. Jung, F. Chesneau, M. Mendez, H.A. Gasteiger, M. Piana, J. Electrochem. Soc. 164 (2017) A400.
4. R. Jung, M. Metzger, F. Maglia, C. Stinner, H.A. Gasteiger, J. Electrochem. Soc. 164 (2017) A1361.
5. R. Jung, M. Metzger, F. Maglia, C. Stinner, H.A. Gasteiger, J. Phys. Chem. Lett. 8 (2017) 4820.
6. A.T.S. Freiberg, M.K. Roos, J. Wandt, R. de Vivie-Riedle, H.A. Gasteiger, J. Phys. Chem. A 122 (2018) 8828.
7. J. Wandt, A.T.S. Freiberg, R. Thomas, Y. Gorlin, A. Siebel, R. Jung, H.A. Gasteiger, M. Tromp, J. Mater. Chem. A 4 (2016) 18300.
8. S. Solchenbach, G. Hong, A.T.S. Freiberg, R. Jung, H.A. Gasteiger, J. Electrochem. Soc. 165 (2018) A3304.
E-mail hubert.gasteiger@tum.de