Chemo-Mechanically Robust Li-Rich Oxide Cathode Interface Enabled By Ion-Conductive and Antioxidant Binder

Lithium-rich manganese-based oxide (LRMO), characterized by distinctive anionic redox activity, has attracted considerable interest as a cathode candidate owing to the low cost and high energy density potential. However, their practical implementation is severely impeded by the intrinsically sluggish kinetics of the anionic redox reaction and the accompanying interfacial side reactions. Herein, a sodium phytate (SP) crosslinked PVDF binder is developed to enhance interfacial ion transport and suppress mechanochemical degradation from surface oxygen inactivation in LRMO. By tailoring the PVDF crystalline phase for Li⁺ transport and introducing polar groups for enhanced binding, SP ensures a more uniform distribution of electrode components. More importantly, the SP suppresses irreversible surface lattice oxygen oxidation in LRMO, and thus quench the release of reactive oxygen species (ROS) and gaseous O₂. Thereby, the LRMO@PVDF/SP electrode exhibits substantially enhanced chemo-mechanical stability and an optimized cathode electrolyte interphase (CEI). It delivers exceptional initial Coulombic efficiency (95%) and discharge capacity (322 mAh/g at 0.1 C), as well as markedly improved cycling stability (maintaining ∼90% capacity retention after 400 cycles at 1 C). This work provides a facile yet scalable strategy for stabilizing the surface lattice oxygen of LRMO cathodes, paving the way for their commercial application.