Role of SEI layer growth in fracture probability in lithium‐ion battery electrodes

Abstract Aging models are necessary to accurately predict the SOH evolution in lithium ion battery systems when performing durability studies under realistic operatings, specifically considering time-varying storage, cycling, and environmental conditions, while being computationally efficient. This paper extends existing physics-based reduced-order capacity fade models that predict degradation resulting from the solid electrolyte interface (SEI) layer growth and loss of active material (LAM) in the graphite anode. Specifically, the physics of the degradation mechanisms and aging campaigns for various cell chemistries are reviewed to improve the model fidelity. Additionally, a new calibration procedure is established relying solely on capacity fade data and results are presented including extrapolation/validation for multiple chemistries. Finally, a condition is integrated to predict the onset of lithium plating. This allows the complete cell model to predict the incremental degradation under various operating conditions, including fast charging.

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Ultrathin Silicon Nanowires Produced by a Bi-Metal-Assisted Chemical Etching Method for Highly Stable Lithium-Ion Battery Anodes

NANO ◽

10.1142/s1793292020500769 ◽

2020 ◽

Vol 15 (06) ◽

pp. 2050076

Author(s):

Fang Sun ◽

Zhiyuan Tan ◽

Zhengguang Hu ◽

Jun Chen ◽

Jie Luo ◽

...

Keyword(s):

Lithium Ion Batteries ◽

Lithium Ion Battery ◽

Silicon Nanowires ◽

Chemical Etching ◽

Silicon Nanowire ◽

High Capacity ◽

Lithium Ion ◽

Average Diameter ◽

Sei Layer ◽

Metal Assisted Chemical Etching

Silicon is widely studied as a high-capacity lithium-ion battery anode. However, the pulverization of silicon caused by a large volume expansion during lithiation impedes it from being used as a next generation anode for lithium-ion batteries. To overcome this drawback, we synthesized ultrathin silicon nanowires. These nanowires are 1D silicon nanostructures fabricated by a new bi-metal-assisted chemical etching process. We compared the lithium-ion battery properties of silicon nanowires with different average diameters of 100[Formula: see text]nm, 30[Formula: see text]nm and 10[Formula: see text]nm and found that the 30[Formula: see text]nm ultrathin silicon nanowire anode has the most stable properties for use in lithium-ion batteries. The above anode demonstrates a discharge capacity of 1066.0[Formula: see text]mAh/g at a current density of 300[Formula: see text]mA/g when based on the mass of active materials; furthermore, the ultrathin silicon nanowire with average diameter of 30[Formula: see text]nm anode retains 87.5% of its capacity after the 50th cycle, which is the best among the three silicon nanowire anodes. The 30[Formula: see text]nm ultrathin silicon nanowire anode has a more proper average diameter and more efficient content of SiOx. The above prevents the 30[Formula: see text]nm ultrathin silicon nanowires from pulverization and broken during cycling, and helps the 30[Formula: see text]nm ultrathin silicon nanowires anode to have a stable SEI layer, which contributes to its high stability.

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