石墨对锂离子软包电池快速充电和放电条件的动态面内异质和反向响应,Small Science

当前位置： X-MOL 学术 › Small Sci. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

石墨对锂离子软包电池快速充电和放电条件的动态面内异质和反向响应
Small Science ( IF 11.1 ) Pub Date : 2023-04-19 , DOI: 10.1002/smsc.202200067
Abigale P. Monasterial ₁ , Peter J. Weddle ₁ , Kristen Atkinson ₁ , David S. Wragg ₂ , Andrew M. Colclasure ₁ , Francois L. E. Usseglio-Viretta ₁ , Natalie Seitzman ₃ , Jun-Sang Park ₄ , Jonathan Almer ₄ , Kandler Smith ₁ , Donal P. Finegan ₁

Affiliation

改善锂离子电池快速充电的解决方案主要集中在减轻平面内锂化梯度，而对平面内异质性以及如何解决它们知之甚少。在此，高速同步加速器X射线衍射（XRD）在6C充电和2C放电过程中在空间和时间上解析了石墨锂化。在运行过程中的每个时刻，软包电池的锂化状态都存在相当大的差异。一些区域比其他区域对操作更敏感，在充电期间早期达到完全锂化，并在放电期间完全脱锂。尽管电压长时间保持在 2.8 V，但电池内的其他区域在放电过程中从未完全脱锂。使用时间分辨 XRD 数据，计算出局部电流密度 (mA cm ^-2）在石墨表面显示出意外发生的局部反转电流密度，其中观察到石墨区域在充电过程中脱锂，在放电过程中锂化。针对具有空间变化微观结构曲折度的石墨电极开发了伪 3D 模型，以显示微观结构异质性如何影响空间电荷动力学。该模型无法预测电池内观察到的复杂的平面内电荷行为。因此，基于均匀电极假设的基于物理的充电协议可能会低估充电动力学的局部变化和锂镀层的发生。

"点击查看英文标题和摘要"

Dynamic In-Plane Heterogeneous and Inverted Response of Graphite to Fast Charging and Discharging Conditions in Lithium-Ion Pouch Cells

Solutions for improving fast charging of lithium-ion batteries have largely focused on alleviating through-plane lithiation gradients while little is understood about in-plane heterogeneities and how to resolve them. Herein, high-speed synchrotron X-ray diffraction (XRD) resolves graphite lithiation spatially and temporally during 6 C charging and 2 C discharging. At every point during operation, considerable differences in the state of lithiation across the pouch cell are present. Some regions are more responsive to operation than others, reaching full lithiation early during charge and full delithiation during discharge. Other regions within the cell never fully delithiate during discharge, despite a prolonged voltage hold at 2.8 V. Using time-resolved XRD data, the calculated local current density (mA cm⁻²) at the graphite surface shows an unexpected occurrence of local inverted current densities where regions of graphite are observed to delithiate during charging and lithiate during discharging. A pseudo-3D model is developed for the graphite electrode with spatially varying microstructural tortuosity to show how microstructural heterogeneity could influence spatial charge dynamics. The model could not predict the complex in-plane charge behavior observed within the cell. Consequently physics-based charging protocols based on homogeneous electrode assumptions may underestimate the local variations in charge dynamics and occurrence of lithium plating.

更新日期：2023-04-19

点击分享查看原文

点击收藏

公开下载

阅读更多本刊新发论文