Strain-alleviated Ni-rich cathodes with inorganic interphases for sustainable fast-charging Li-ion batteries

Fast-charging Li-ion batteries are essential for realizing a charge-anxiety-free era in portable electronics and electric transportation. Although extensive efforts have focused on fast-charging industry-favored Ni-rich cathodes, the fundamental mechanisms limiting performance under simultaneous high-voltage and high-rate conditions remain unresolved. To address this long-standing challenge, we designed a P surface-treated B and Mg co-doped high-Ni (∼90%) cathode with an engineered grain texture and a robust, inorganic-rich surface with reliable thermal properties. The B-modified nanograin architecture, combined with Mg-induced lattice pillaring, buffers internal stress (<2%) and alleviates anisotropic strain evolution. Simultaneously, the inorganic-rich P/B surface layer protects the cathode from electrolyte-driven degradation via surface passivation and the suppression of lattice-oxygen evolution. The engineered cathode sustains 1000 cycles in a pouch-cell configuration under 4 C charging, successfully retaining ∼80% reversible capacity. By concurrently optimizing the bulk microstructure and interphase via a scalable, cost-effective strategy, this work provides a sustainable pathway towards next-generation fast-charging Li-ion batteries.