The fast-charging capability is critical for the wide adoption of electric vehicles (EVs), which, however, can result in lithium (Li) plating on the graphite anode and thus aggravate cell degradation and increase the safety risk. Li plating is also prone to occur during charging at low temperatures. In this work, we fabricate Li-ion full cells in transparent glass capillaries to probe the real-time dynamic evolution of the lithiated phases throughout the graphite anode toward the onset of lithium plating during fast charging and under low temperatures. We observed that Li plating can occur well before 70% state of charge (SOC), even at a low C-rate and at room temperature. Our operando experiments provide the direct proof that subtle features in the electrochemical responses are caused by the Li plating, which can be utilized to improve battery management strategy. Mathematical simulations confirm that the local overpotential due to the strong concentration polarization is the root cause of the axial reaction heterogeneity in the graphite anode and the Li plating on the fully lithiated particles.

中文翻译：

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透明锂离子全电池中锂电镀开始的原位显微诊断

快速充电能力对于电动汽车 (EV) 的广泛采用至关重要，然而，这会导致石墨阳极上镀锂 (Li)，从而加剧电池退化并增加安全风险。低温充电时也容易发生镀锂。在这项工作中，我们在透明玻璃毛细管中制造了锂离子全电池，以探测在快速充电和低温下整个石墨阳极的锂化相在锂电镀开始时的实时动态演变。我们观察到，即使在低 C-rate 和室温下，锂电镀也可以在 70% 充电状态 (SOC) 之前发生。我们的操作实验提供了直接证据，表明电化学响应中的细微特征是由镀锂引起的，可用于改进电池管理策略。数学模拟证实，由于浓差极化引起的局部过电位是石墨负极轴向反应不均匀性和全锂化颗粒上镀锂的根本原因。