Nanodot-heterostructure-engineered cathode-electrolyte interphase for stable lithium-rich manganese-based oxide cathodes

High-voltage Li-rich Mn-based oxide (LRMO) cathodes are promising for breaking through the energy density limits of lithium-ion batteries, yet their practical application remains limited by electrochemical performance degradation caused by unstable cathode-electrolyte interphase (CEI) evolution during long-term cycling. To address this issue, we propose a novel surface modification strategy using La0.7Sr0.3MnO3−σ (LSMO) nanodots, which exhibit high electronic conductivity and excellent corrosion resistance. These nanodots act as stable anchoring sites, facilitating the formation of a robust CEI on LRMO. The LSMO-modified cathode demonstrates significantly improved anionic redox reversibility, effectively mitigating transition metal migration and lattice oxygen loss. Furthermore, the optimized interfacial electrochemical kinetics ensure sustained rapid Li+ diffusion throughout cycling, while the formation of a stable trilayer CEI structure suppresses electrolyte decomposition. Benefiting from these synergistic effects, the LSMO nanodot-engineered LRMO cathode delivers outstanding cycling stability, retaining 97.4 % capacity after 300 cycles at 1 C. This work not only highlights the critical role of nanodot heterostructures in stabilizing CEI but also provides a new approach to designing high-voltage cathodes with superior interfacial compatibility and long-term durability.