Fluoride-Ion-Mediated Fabrication of Cerium-Incorporated Ternary Layered Double Hydroxide Microflowers for Enhanced Chlorine Storage

Abstract

Layered double hydroxides (LDHs) continue to encounter obstacles, including limited structural stability and low intrinsic conductivity, hindering their application in reversible chloride storage. Herein, an approach integrating precise surface electronic modulation with the rational design of heterostructures featuring tailored morphology is proposed. By introducing anionic competitive coordination, conventional 2D LDH nanosheets are transformed into 3D hollow microflowers. Benefiting from the synergistic coordination and oxyphilic of Ce to stabilize the 3D morphology, Ce-doped NiFe LDH (Ce-NiFe LDH) and Ce-NiFe LDH@CeF₃ heterostructure are further constructed, yielding cathodes with exceptional performance for chloride ion batteries (CIBs). The optimized Ce_0.3NiFe-Cl LDH@CeF₃ shows a high chloride storage capacity of 395.7 mAh g⁻¹ and stable cycling performance of 222.28 mAh g⁻¹ after 500 cycles at 300 mA g⁻¹ with an average Coulombic efficiency of 99.65%. The unique Ce_0.3NiFe-Cl LDH@CeF₃ heterostructure also alleviates the volumetric expansion during Cl intercalation/de-intercalation, achieving the low-strain CIBs cathode (ΔV ≈ 0.84%). Moreover, the introduction of Ce enhances the density states near the Fermi level and facilitates interfacial charge redistribution, leading to a boost Cl⁻/electrons transport kinetics. This work elucidates the chloride storage mechanism in rare-earth-doped LDH-based heterostructures and offers a robust pathway for designing high-performance CIB cathodes.