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Design Principles to Govern Electrode Fabrication for the Lithium Trivanadate Cathode

Authors :
Kenneth J. Takeuchi
Amy C. Marschilok
Alan C. West
Nicholas W. Brady
Karthik S. Mayilvahanan
Lei Wang
Alison H. McCarthy
Esther S. Takeuchi
Source :
Journal of The Electrochemical Society. 167:100503
Publication Year :
2020
Publisher :
The Electrochemical Society, 2020.

Abstract

A full depth of discharge mathematical model for the lithium trivanadate cathode, considering lithiation of the layered α-phase, phase change, and lithiation of the rock-salt like β-phase at lower potentials, is developed. The coupled electrode-scale and crystal-scale model is fit to electrochemical data, and additionally validated with operando EDXRD. There is good agreement between the simulated and measured spatial variation of the volume fraction of the β-phase. This mathematical model is used to guide electrode fabrication, accounting for both ionic and electronic transport effects. Values of three design parameters—electrode thickness, porosity, and volume fraction of conductor—are identified, and the sensitivity of the energy density to these design parameters is quantified. The model is also used to investigate electrode design to create electrodes that deliver the maximum achievable energy density under the constraint that the α to β-phase transition is avoided, since phase change has been demonstrated to reduce cycle life. The energy density sacrificed to avoid phase change decreases at higher discharge rates, but the target values for electrode fabrication remain the same as those when optimizing the electrode for the full depth of discharge.

Details

ISSN :
19457111 and 00134651
Volume :
167
Database :
OpenAIRE
Journal :
Journal of The Electrochemical Society
Accession number :
edsair.doi...........f9997a95d9e352af6221ef3cd84d64a7
Full Text :
https://doi.org/10.1149/1945-7111/ab91c8