Bulk-Interface Synergy Enables Stable High-Voltage P2-Type Layered Oxide Cathodes for Fast-Charging Sodium-Ion Batteries.
basic_science · Level V
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- Record sourced from PubMed, PMID 41774548.
- Also identified by DOI 10.1021/acsnano.6c01913.
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Abstract
P2-type layered oxides hold great promise for high-energy sodium-ion batteries (SIBs) but are hindered by irreversible P2-O2 transitions and interfacial degradation that accelerate capacity fading. Herein, we present a bulk-interface dual-engineering strategy through synergistic Mg<sup>2+</sup> doping and CeO<sub>2</sub> surface modulation to overcome these challenges. The designed P2-type Na<sub>0.67</sub>Mg<sub>0.1</sub>Ni<sub>0.23</sub>Mn<sub>0.67</sub>O<sub>2</sub>-CeO<sub>2</sub> (NNMMO-Ce) cathode integrates structural reinforcement and redox synergy: bulk Mg<sup>2+</sup> stabilizes the lattice, widens Na<sup>+</sup> diffusion channels, and suppresses destructive high-voltage transitions, while a conformal CeO<sub>2</sub> nanolayer buffers lattice strain (∼0.9%), prevents intragranular cracking, and enables the storage and release of (O<sub>2</sub>)<sup><i>n</i>-</sup> species through reversible Ce<sup>3+</sup>/Ce<sup>4+</sup> redox activity. This coupled mechanism coordinates electron-ion transport, minimizes polarization effects, and significantly reduces charge transfer resistance as well as the escape of lattice oxygen. Consequently, NNMMO-Ce exhibits superior performance with 94.0% capacity retention at 0.1 C and 66.2 mAh g<sup>-1</sup> at 20 C, along with highly reversible P2-OP4 transitions and >35-fold enhanced Na<sup>+</sup> diffusion. When paired with a hard-carbon anode, the full cell delivers a high energy density of 258.97 Wh kg<sup>-1</sup> and excellent cycling stability over 2-4.35 V. This work establishes a cooperative bulk-interface strategy for constructing high-capacity, fast-charging, and long-lived SIB cathodes.