Abstract

For advancing lithium-ion battery (LIB) technologies, a detailed understanding of battery degradation mechanisms is important. In this article, experimental observations are provided to elucidate the relation between side reactions, mechanical degradation, and capacity loss in LIBs. Graphite/Li(Ni1/3Mn1/3Co1/3)O2 cells of two very different initial anode/cathode capacity ratios (R, both R > 1) are assembled to investigate the electrochemical behavior. The initial charge capacity of the cathode is observed to be affected by the anode loading, indicating that the electrolyte reactions on the anode affect the electrolyte reactions on the cathode. Additionally, the rate of “marching” of the cathode is found to be affected by the anode loading. These findings attest to the “cross-talk” between the two electrodes. During cycling, the cell with the higher R value display a lower columbic efficiency, yet a lower capacity fade rate as compared to the cell with the smaller R. This supports the notion that columbic efficiency is not a perfect predictor of capacity fade. Capacity loss is attributed to the irreversible production of new solid electrolyte interphase (SEI) facilitated by the mechanical degradation of the SEI. The higher capacity fade in the cell with the lower R is explained with the theory of diffusion-induced stresses (DISs).

Document Type

Article

Publication Date

7-28-2015

Notes/Citation Information

Published in Journal of The Electrochemical Society, v. 162, issue 10, A2026-A2035.

© The Author(s) 2015. Published by ECS.

This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.

Digital Object Identifier (DOI)

https://doi.org/10.1149/2.0291510jes

Funding Information

The authors acknowledge the BATT Program and the U.S. Department of Energy, as well as National Science Foundation Award No. 1355438 (Powering the Kentucky Bioeconomy for a Sustainable Future) for partially funding this project.

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