Strain‐Induced Magnetic Ordering Unlocks Spin‐Conserved Catalysis in Lithium‐Oxygen Batteries

Abstract

ABSTRACT Designing advanced ferromagnetic catalysts with robust intrinsic magnetism and efficient spin polarization is critical for enabling spin‐selective electron transfer between triplet O 2 and singlet Li 2 O 2 in lithium‐oxygen batteries (LOBs), yet controlling magnetic ordering and spin states at the atomic scale remains a fundamental challenge. Here, we present a lattice tensile strain engineering to construct strained CoS 2 anchored on reduced graphene oxide (s‐CoS 2 /rGO), achieving significantly enhanced ferromagnetic exchange interactions and spin polarization. Experimental and theoretical analyses reveal that a ∼4% tensile strain along the (111) plane induces spontaneous parallel alignment of atomic magnetic moments, generating intrinsic magnetic anisotropy and coherent single‐domain architectures. This lattice distortion enhances d‐p orbital hybridization and establishes spin‐polarized conduction channels at Co─S active sites, enabling parallel‐spin electron transfer to adsorbed O 2 and effectively bypassing the spin‐flip energy barrier associated with O 2 /Li 2 O 2 conversion. As a result, the s‐CoS 2 /rGO catalyst exhibits elevated spin‐polarized current densities, a markedly reduced O 2 dissociation barrier, and superior catalytic kinetics, delivering ultra‐long cycling exceeding 2000 h at 200 mA g −1 . This work offers a general approach for designing high‐performance ferromagnetic catalysts and highlights the critical role of spin‐state engineering in advancing next‐generation LOB technologies.