Aging Mechanisms of Electrode Materials in Lithium-Ion Batteries for Electric Vehicles

Abstract

Electrode material aging leads to a decrease in capacity and/or a rise in resistance of the whole cell and thus can dramatically affect the performance of lithium-ion batteries. Furthermore, the aging phenomena are extremely complicated to describe due to the coupling of various factors. In this review, we give an interpretation of capacity/power fading of electrode-oriented aging mechanisms under cycling and various storage conditions for metallic oxide-based cathodes and carbon-based anodes. For the cathode of lithium-ion batteries, the mechanical stress and strain resulting from the lithium ions insertion and extraction predominantly lead to structural disordering. Another important aging mechanism is the metal dissolution from the cathode and the subsequent deposition on the anode. For the anode, the main aging mechanisms are the loss of recyclable lithium ions caused by the formation and increasing growth of a solid electrolyte interphase (SEI) and the mechanical fatigue caused by the diffusion-induced stress on the carbon anode particles. Additionally, electrode aging largely depends on the electrochemical behaviour under cycling and storage conditions and results from both structural/morphological changes and side reactions aggravated by decomposition products and protic impurities in the electrolyte.

Understanding the crack formation of graphite particles in cycled commercial lithium-ion batteries by focused ion beam - scanning electron microscopy

“…To be noted, understanding the degradation mechanisms of LIBs is beneficial to address the life time and safety challenges, to make precise lifetime predictions, and to improve the battery performance. [15] It was found that compared to the stable LiFeO 4 electrode, [16] the stability of graphite electrode is more critical to the long-term failure and degradation of the corresponding LIB. [17][18][19][20] Therefore, investigating the degradation mechanism of graphite electrodes in Graphite-LiFeO 4 batteries would help us understand the decline of battery performance along cycles.…”

A model‐based and data‐driven joint method for state‐of‐health estimation of lithium‐ion battery in electric vehicles

“…[30][31][32][33] The expended lithium ions are no longer available for cycling between battery electrodes, leading to capacity fade. The main reason for battery degradation is the loss of lithium inventory and the loss of active material of positive or negative electrodes.…”

“…The main reason for battery degradation is the loss of lithium inventory and the loss of active material of positive or negative electrodes. [30][31][32][33] The expended lithium ions are no longer available for cycling between battery electrodes, leading to capacity fade. Moreover, the loss of active mass of electrodes leads to both capacity fade and the increase in the battery impedance.…”

Analysis of the effect of resistance increase on the capacity fade of lithium ion batteries

“…The degradation of lithium ion batteries occurs due to various chemical degradation mechanisms such as electrolyte decomposition and reduction resulting in solidelectrolyte interphase (SEI) formation, active material dissolution, and gas evolution and mechanical degradation mechanisms such as formation of cracks in active materials and loss of contact from current collector. [9][10][11][12] This degradation behavior is typically studied by cycling the batteries with a fixed protocol for a long duration. A typical protocol consists of charging the battery in the constant current constant voltage (CCCV) mode till a specified current cutoff is reached, resting the battery for a fixed time, discharging at a fixed current till a voltage cutoff is reached and further resting the battery for a fixed duration.…”

“…The degradation of lithium ion batteries occurs due to various chemical degradation mechanisms such as electrolyte decomposition and reduction resulting in solid‐electrolyte interphase (SEI) formation, active material dissolution, and gas evolution and mechanical degradation mechanisms such as formation of cracks in active materials and loss of contact from current collector . This degradation behavior is typically studied by cycling the batteries with a fixed protocol for a long duration.…”