Layered double hydroxides cathode for long-lifespan dual ion batteries

Dual-ion batteries (DIBs) have garnered significant attention owing to their high volumetric energy density, cost-effectiveness and environmental friendliness. However, the most commonly used graphite cathode suffers from substantial volume changes and sluggish ion diffusion kinetics, severely limiting its practical applications. Herein, we report a perchlorate-intercalated NiFe layered double hydroxide (NiFe-ClO 4 LDH) prepared by a facile co-precipitation route as an anion-host cathode for DIBs. NiFe-ClO 4 LDH delivers a maximum discharge specific capacity of 194.4 mAh g −1 and an ultralong cycle life of 1600 cycles at 100 mA g −1 , with negligible capacity degradation (only 0.019% per cycle). Enabled by its expanded interlayer galleries (8.38 Å), NiFe-ClO 4 LDH undergoes only 13.6% volume variation throughout the entire cycling process. Mechanistic studies confirm the reversible shuttling of ClO 4 − within the LDH galleries, coupled with reversible Ni/Fe redox in the host layers for charge compensation. Moreover, interlayer water plays a critical role in preserving the layered framework during cycling, thereby sustaining the electrochemical stability. This work establishes LDH-based interlayer anion engineering as an effective strategy to realize high-rate and long-life anion-storage cathodes for DIBs.