Particle-wide cation anchoring enables strain-suppressed high-voltage stability in Co-free Ni-rich cathodes

초록

Co-free Ni-rich layered oxides are promising cathodes for next-generation Li-ion batteries but suffer from structural degradation driven by anisotropic c-lattice collapse. Recent studies suggest that cation anchoring, defined as the periodic arrangement of Ni2+ ions within the Li slabs, can enhance structural rigidity when high valence dopants induce Li/Ni ordering. However, conventional doping typically causes dopant segregation at grain boundaries, confining cation anchoring to localized regions and limiting its strain-mitigating effect. Here, we demonstrate that homogeneous Mo6+ doping throughout the primary particles of LiNi0.9Mn0.1O2 achieved via a cetyltrimethylammonium bromide assisted co-precipitation route, induces particle-wide cation anchoring. This ordering periodically aligns Ni2+ ions within the Li layers, forming structural pillars that suppress anisotropic lattice contraction, reducing c-lattice shrinkage to one-fifth of that in the undoped material. As a result, the cathode retains 91.4% of its initial capacity after 100 cycles at 0.5 C within 2.7–4.5 V, highlighting bulk cation anchoring as a viable design principle for durable Co-free Ni-rich cathodes.

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