Direct regeneration enables high‐value recovery of spent layered oxide cathodes, but their high‐voltage reuse requires stabilization of both regenerated surface and lattice oxygen beyond bulk compositional restoration. Here, we report a high‐voltage upcycling strategy for spent LiNi _0.6 Co _0.2 Mn _0.2 O ₂ (NCM) based on near‐surface fluorine (F) regulation of residual rock‐salt layers. Molten‐salt relithiation recovers Li content and layered bulk framework, whereas subsequent fluorine treatment converts the remaining inert surface reconstruction into a thin F‐enriched rock‐salt interphase. Rather than impeding Li ⁺ transport, this interphase stabilizes the reconstructed surface, reduces oxygen defects, and mitigates electrolyte‐induced interfacial degradation. The resulting cathode with F‐enriched rock‐salt surface (RFNCM) delivers 208.7 mAh g ⁻¹ at 0.1 C within 3.0‐4.6 V, and retains 80.28% capacity after 400 cycles at 1 C and 25°C, and 80.93% after 200 cycles at 50°C. In situ X‐ray diffraction and gas‐evolution measurements reveal more homogeneous high‐voltage structural evolution and suppressed oxygen release, respectively. According to analysis results of XPS, in situ Raman and Density functional theory calculations, these improvements can be attributed to strengthened Ni─O interactions and increased oxygen‐vacancy formation energies after fluorine incorporation. This work converts an unavoidable reconstruction product into a protective interphase for high‐voltage reuse of spent layered oxide cathodes.

Simultaneously activating metal and lattice oxygen sites to construct a compatible multi-mechanism catalysis is expected for the oxygen evolution reaction (OER) by providing highly available active sites and mediate catalytic activity/stability, but significant challenges remain. Herein, Fe and S dually modulated NiFe oxyhydroxide (R-NiFeOOH@SO₄) is conceived by complete reconstruction of NiMoO₄·xH₂O@Fe,S during OER, and achieves compatible adsorbate evolution mechanism and lattice oxygen oxidation mechanism with simultaneously optimized metal/oxygen sites, as substantiated by in situ spectroscopy/mass spectrometry and chemical probe. Further theoretical analyses reveal that Fe promotes the OER kinetics under adsorbate evolution mechanism, while S excites the lattice oxygen activity under lattice oxygen oxidation mechanism, featuring upshifted O 2p band centers, enlarged d-d Coulomb interaction, weakened metal-oxygen bond and optimized intermediate adsorption free energy. Benefiting from the compatible multi-mechanism, R-NiFeOOH@SO₄ only requires overpotentials of 251 ± 5/291 ± 1 mV to drive current densities of 100/500 mA cm⁻² in alkaline media, with robust stability for over 300 h. This work provides insights in understanding the OER mechanism to better design high-performance OER catalysts.