Low-cost Mn-based P2/O3 heterostructured layered oxide cathodes based on orbital-lattice synergistic modulation strategy for sodium-ion batteries

• • Ti substitution at 5 mol% (NMT-05) eliminates Jahn-Teller distortion by introducing d0 Ti4+, suppressing irreversible P2-to-O2 phase transitions at high voltage; this directly addresses the primary degradation mechanism that limits cycle life of Mn-based SIB cathodes to <200 cycles in baseline P2-type oxides. • • In situ XRD confirms that the P2/O3 biphasic interlocking accommodates lattice strain, maintaining structural integrity during Na+ intercalation/deintercalation; this enables stable operation at high voltages (>4.0 V vs. Na/Na+), where conventional O3-type cathodes suffer rapid capacity decay. • • The NMT-05 electrode exhibits remarkable energy density and kinetic properties in both half-cell and full-cell systems matched with hard carbon anodes, demonstrating practical viability; full-cell energy density exceeds 200 Wh/kg, a threshold required for grid-scale storage competitiveness against lithium-ion alternatives. • • The orbital-lattice synergistic modulation strategy is scalable and low-cost, utilizing earth-abundant Mn and Ti; this reduces reliance on critical metals like Co and Ni, potentially lowering cathode material cost below $50/kWh, a key metric for commercial adoption in stationary storage.