O3-type cathodes hold considerable promise in achieving rapid commercialization due to high energy density. However, severe structural/interfacial deterioration, along with kinetic hindrance, typically resulting in rapid capacity fading and serious safety risk at elevated cut-off voltages. Herein, inspired from solubility limitation of hetero-elements, synchronous surface-to-bulk multifunctionally full-scale modified O3-NaNi1/3Fe1/3Mn1/3O2 is proposed to maintain its state of health (SOH). The perovskite-type CaZrO3 protective layer in situ formed on the surface of primary particles, helps to construct a stable cathode-electrolyte-interphase architecture, mitigate the unexpected interfacial side reactions and prevent transition metal dissolution. Simultaneously, Ca2+ pillars, robust Zr-O bonds and the highly electronegative F- are adequately anchored into ternary lattice sites of Na-TM-O, respectively, thereby reinforcing the TMO6 octahedra and facilitating Na+ diffusion. Notably, the intrinsic lattice strain is effectively alleviated due to an additional intergrowth phase transition of P3-OP2. More impressively, migration of Jahn-Teller distorted Fe4+O6 is further restrained, originating from the strengthened coordination environment under deep-desodiation state. Consequently, as-designed NFM-CZF achieves an impressive rate capability and a remarkable capacity retention of 83.8 % after 300 cycles at 2 C. This elaborate work shed valuable insight into mechanism of regulating internal full Wyckoff-site and external surface structure for sodium-ion batteries with enhanced durability.
Keywords: Fe distortion; O3-type layered cathode; Triple-lattice site doping; perovskite phase coating.
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