Physics-based modeling of cyclic and calendar aging of LIBs with Si-Gr composite anodes

TL;DR

This paper presents a physics-based model for lithium-ion battery degradation that accounts for silicon anode effects, enabling better understanding and optimization of battery lifespan under various conditions.

Contribution

A novel physics-based model that separates different degradation mechanisms in silicon-anode lithium-ion batteries under diverse cycling and storage protocols.

Findings

Model can distinguish SEI growth from silicon particle cracking.

Impact of check-up frequency on storage degradation analyzed.

Degradation mechanisms linked to operating conditions for optimization.

Abstract

Higher energy density and longer lifetime are the requirements for next-generation lithium-ion batteries. A promising anode material is silicon, which offers high specific capacity, but its significant volume change during lithiation and delithiation enormously reduces battery lifetime. A physical understanding of the processes degrading the battery is key to mitigate this effect and advance in the field. We develop a physics-based model to describe degradation during battery cycling under various protocols and storage conditions, with varying check-up (CU) frequencies. The model can disentangle basic degradation mechanisms, such as the growth of the Solid-Electrolyte Interphase (SEI), from silicon mechanisms, such as particle cracking, SEI growth on cracks, and loss of active material (LAM). We investigate the impact of CUs on the observed storage degradation and the reason behind the increased degradation in batteries, including silicon in the anode. Additionally, we relate the observed degradation to operating conditions, enabling future optimization of battery use and design.