Rational design of Li-rich hybrid cathodes with stiff redox-active interstitial networks enabling local environment engineering for reversible oxygen redox

Li-rich manganese-based cathode (LRM) materials are among the most promising candidates for next-generation high-energy lithium-ion batteries; however, their practical implementation is restricted by low initial coulombic efficiency, voltage decay, structural instability, and sluggish reaction kinetics. To address these intrinsically coupled limitations, we propose a rational electrode-level hybrid architecture that deliberately physical integrates layered LRM with a mechanically stiff and redox-active cation-disordered rock-salt (DRX) phase to construct interstitial three-dimensional transport networks. In this design, micron-sized LRM particles preserve the layered diffusion backbone, while nanosized DRX particles are strategically embedded within interparticle gaps to form a percolated, high-rigidity network that engineers local chemical and mechanical environments. This spatially programmed coupling regulates reversible oxygen redox, stabilizes the TM-O framework, suppresses oxygen release and transition-metal dissolution, and homogenizes stress evolution during cycling. The optimized physical hybrid cathode delivers enhanced initial coulombic efficiency (76.36%), improved 300-cycle capacity retention (73.1% at 1 C), reduced voltage decay (1.38 mV per cycle), and superior rate capability (162.9 mAh·g^-1 at 5 C). Importantly, these advantages are retained in laboratory-scale thick electrodes, demonstrating improved structural integrity and kinetic uniformity. This work establishes a scalable hybrid-electrode design paradigm that enables reversible oxygen redox through local environment engineering in Li-rich cathodes.