Cathode-electrolyte interphase (CEI) formation is a key process that impacts the performance of lithium-ion batteries. In this work, we characterized the composition and stoichiometry of CEI layer on LiNi_xMn_yCo_1-x-yO₂ (NMC) cathodes via a novel combination of quantitative correlation analysis of X-ray photoelectron spectra and binder-free cathode formulation. By comparing the CEI formation in NMC-based cells with lithium, graphite and lithium titanate anodes, we demonstrate a CEI formation pathway via migration of surface species that originally formed on the anode side. A case study of cathodes coated by atomic layer deposition with a thin layer of Al₂O₃ demonstrates that anode-to-cathode migration can be mitigated by ALD cathode coatings. This work highlights the importance of anode-mediated processes in order to correctly interpret surface phenomena on the cathode side and to guide further development of surface protection strategies.

阴极电解质相间（CEI）的形成是影响锂离子电池性能的关键过程。在这项工作中，我们通过X射线光电子能谱的定量相关分析和无粘结剂阴极配方的新型结合，对LiNi _x Mn _y Co _1-xy O ₂（NMC）阴极上CEI层的组成和化学计量进行了表征。通过比较具有锂，石墨和钛酸锂阳极的基于NMC的电池中的CEI形成，我们证明了CEI的形成途径是通过最初在阳极侧形成的表面物质的迁移而实现的。原子层沉积涂有薄薄的Al ₂ O ₃涂层的阴极的案例研究证明ALD阴极涂层可以减轻阳极到阴极的迁移。这项工作突出了阳极介导的过程的重要性，以便正确地解释阴极侧的表面现象并指导表面保护策略的进一步发展。