Pre-lithiation of anode materials can be an effective method to compensate active lithium loss which mainly occurs in the first few cycles of a lithium ion battery (LIB), due to electrolyte decomposition and solid electrolyte interphase (SEI) formation at the surface of the anode. There are many different pre-lithiation methods, whereas pre-lithiation using metallic lithium constitutes the most convenient and widely utilized lab procedure in literature. In this work, for the first time, solid state nuclear magnetic resonance spectroscopy (NMR) is applied to monitor the reaction kinetics of the pre-lithiation process of graphite with lithium. Based on static ⁷Li NMR, we can directly observe both the dissolution of lithium metal and parallel formation of LiC_x species in the obtained NMR spectra with time. It is also shown that the degree of pre-lithiation as well as distribution of lithium metal on the electrode surface have a strong impact on the reaction kinetics of the pre-lithiation process and on the remaining amount of lithium metal. Overall, our findings are highly important for further optimization of pre-lithiation methods for LIB anode materials, both in terms of optimized pre-lithiation time and appropriate amounts of lithium metal.

阳极材料的预锂化可以是一种有效的方法，以补偿主要在锂离子电池（LIB）的前几个循环中发生的活性锂损失，这是由于在锂离子电池表面上的电解质分解和固体电解质中间相（SEI）形成的缘故阳极。有许多不同的预锂化方法，而使用金属锂进行的预锂化构成了文献中最方便和广泛使用的实验室程序。在这项工作中，首次将固态核磁共振波谱（NMR）应用于监测石墨与锂的预锂化过程的反应动力学。基于静态⁷ Li NMR，我们可以直接观察到锂金属的溶解和LiC _x的平行形成随时间变化的NMR谱中的分子种类。还显示出预锂化程度以及锂金属在电极表面上的分布对预锂化过程的反应动力学以及锂金属的剩余量具有强烈影响。总体而言，无论是在优化预锂化时间和适量锂金属方面，我们的发现对于进一步优化LIB阳极材料的预锂化方法都非常重要。