Rational Design of Prussian Blue Analogs Cathodes With "Dual-Channel" Structure for Wide-Temperature-Range Sodium-Ion...

The electrochemical performance of sodium-ion batteries (SIBs) cathodes over a wide temperature (WT) range is crucial, but is fundamentally limited by sluggish kinetics and transition metal dissolution under harsh conditions. Herein, a channel structured Prussian blue analog (MnANP-channel, MAC) featuring unconventional carbon-nitrogen vacancies (V_CN) was designed via a novel "one-step" in situ etching strategy. Theoretical calculations and experimental results reveal that V_CN enhances the intrinsic affinity for transition metals and accelerates the diffusion kinetics of sodium ions. The channel microstructure maximizes active site utilization and facilitates rapid mass and charge transport at the electrode-electrolyte interface. This synergistic interplay between the molecular and microscopic scales, creating a unique "dual-channel" architecture, endows MAC with excellent WT-range adaptability (103.9, 151.4, and 162.1 mAh/g at -50°C, 25°C, and 50°C, respectively), exceptional rate capability (20 A/g), and remarkable long-term cycling stability (≈ 6800 cycles). Critically, the MAC//HC full cell exhibits superior energy density (≈ 309 Wh/kg, based on the total mass of the cathode and anode active materials) and wide-temperature electrochemical performance (-40°C~50°C). Moreover, this versatile synthetic strategy can be extended to diverse PBA compositions (Fe-, FeCo-, FeCoMn-, and FeCoMnNi-ANP), offering great opportunities for rational construction of advanced architectures with targeted functionalities.