Stabilizing the cathode-electrolyte interphase for superior Li-ion batteries

The cathode-electrolyte interphase (CEI) plays a pivotal role in determining the energy density and cycling stability of lithium-ion batteries. However, its complex formation mechanisms, dynamic evolution, and interplay with battery components pose significant challenges for a fundamental understanding and targeted regulation. While prior research has focused on modifying bulk electrolyte solvation structures and applying inert cathode coatings, this perspective analyzes the mechanisms of CEI formation and stabilization, with particular emphasis on cathode pre-interphase engineering, near-surface electric double-layer modulation, and functional coating design. Future research prospects are outlined, highlighting the advanced in situ characterization techniques with high spatiotemporal resolution to probe transient interfacial processes, along with innovative strategies for constructing CEI architectures. • Unresolved formation/evolution mechanisms involving dynamic interfacial processes • Incomplete structure-activity relationships governing cycling stability and high-rate capability • Underexplored design paradigms beyond conventional coating/electrolyte modifications • Insufficient operando characterization techniques with atomic/millisecond spatiotemporal resolution • Lack of scalable engineering approaches for commercial viability in CEI regulation