Journal article

Publication year: 2021

Pages: 070546-

Journal: Journal of The Electrochemical Society

Volume number: 168

Issue number: 7

ISSN: 0013-4651

Open access status: Hybrid

DOI Link: https://doi.org/10.1149/1945-7111/ac13d2

Publisher: The Electrochemical Society

Abstract: 
The use of solid electrolytes in lithium batteries promises to increase their power and energy density, but several challenges still need to be overcome. One critical issue is capacity-fading, commonly ascribed to various degradation reactions in the composite cathode. Chemical, electrochemical as well as chemo-mechanical effects are discussed to be the cause, yet no clear understanding of the mechanism of capacity fading is established. In this work, a model is proposed to interpret the low-frequency impedance of the cathode in terms of lithium diffusion within an ensemble of LiNi1-x-yCoxMnyO2 (NCM) cathode active material particles with different particle sizes. Additionally, an electrochemical technique is developed to determine the electrochemically active mass in the cathode, based on the estimation of the state-of-charge via open circuit potential-relaxation. Tracking the length of lithium diffusion pathways and active mass over 40 charge-discharge cycles demonstrates that the chemo-mechanical evolution in the composite cathode is the major cause for cell capacity fading. Finally, it is shown that single-crystalline NCM is far more robust against chemo-mechanical degradation compared to polycrystalline NCM and can maintain a high cycling stability.

Harvard Citation style: Conforto, G., Ruess, R., Schröder, D., Trevisanello, E., Fantin, R., Richter, F., et al. (2021) Editors' Choice-Quantification of the Impact of Chemo-Mechanical Degradation on the Performance and Cycling Stability of NCM-Based Cathodes in Solid-State Li-Ion Batteries, Journal of The Electrochemical Society, 168(7), p. 070546. https://doi.org/10.1149/1945-7111/ac13d2

APA Citation style: Conforto, G., Ruess, R., Schröder, D., Trevisanello, E., Fantin, R., Richter, F., & Janek, J. (2021). Editors' Choice-Quantification of the Impact of Chemo-Mechanical Degradation on the Performance and Cycling Stability of NCM-Based Cathodes in Solid-State Li-Ion Batteries. Journal of The Electrochemical Society. 168(7), 070546. https://doi.org/10.1149/1945-7111/ac13d2