Coprecipitation‐Enabled Scalable Synthesis of High‐Energy Density Polyanion‐Integrated Disordered Rocksalt Cathodes for Lithium‐Ion Batteries

ABSTRACT Disordered rocksalt cathodes (DRX) represent a compelling platform for cobalt‐ and nickel‐free high‐energy density lithium‐ion batteries. Yet their scalable synthesis remains challenging, especially for metastable DRX chemistries that have been predominantly developed via mechanochemical routes. A prominent example is polyanion‐integrated DRX (DRXPS) cathodes, which rank among the best DRX cathodes reported to date in terms of reversible energy density, but have thus far been synthesized only mechanochemically via low‐temperature ball milling. Here we demonstrate a coprecipitation–enabled solid‐state synthesis of a DRXPS cathode, Li 1.67 Mn 1.5 P 0.17 O 4 , translating a mechanochemical route into a scalable process that is compatible with established cathode manufacturing infrastructure. The workflow programs precursor chemistry via coprecipitation of Mn 2 + with HPO 4 2 − and OH − , followed by a eutectic lithium‐salt‐assisted solid‐state reaction, enabling low‐thermal‐budget DRXPS formation (450°C, 30 min) in air. The reduced thermal budget suppresses particle coarsening and yields a mixed micro‐/nanoscale particle morphology, thereby eliminating the need for post‐synthesis particle pulverization. The resulting cathodes deliver 324 mAh g −1 (935 Wh kg −1 ), demonstrating that high‐energy density DRXPS can be realized within a manufacturing‐compatible workflow. This work establishes a direct pathway toward scalable production of metastable high‐energy density DRXPS cathodes and identifies precursor engineering as the key enabler.