Atomic Interface Engineering of NiFe‐LDH@MXene via Halide Ions for High‐Rate Chloride‐Ion Batteries

Abstract

While layered double hydroxides (LDHs) stand as a typical 2D anion‐intercalated cathodes for chloride ion batteries (CIBs), their electrochemical viability is significantly limited by inherently poor electronic conductivity and sluggish interlayer transport kinetics, particularly under high current density operations. Herein, a space‐charge heterostructure through electrostatic self‐assembly of positively charged NiFe LDH nanosheets and negatively charged MXene layers is constructed. This strategy establishes a built‐in electric field at the atomic interface via electron‐withdrawing Cl− “bridge”, which enhances Cl adsorption through spatial decoupling of MXene's electron highways and LDH's ion‐storage channels. The resulting 1NiFe‐LDH@2MXene heterostructure cathode achieves a remarkable reversible capacity of 119.1 mAh g−1 at 1000 mA g−1 over 1000 cycles with an ultralow capacity decay rate of 0.034% per cycle. Comprehensive characterizations disclose that the enhanced Cl⁻ intercalation kinetics of NiFe‐LDH@MXene heterostructure is governed by increased pseudo‐capacitive storage through integration of MXene and the substantial electron accumulation at the LDH@MXene heterointerface, creating a built‐in electric field that lowers the effective Schottky barrier. By extending this method to F⁻ and Br⁻‐intercalated analogues for fluoride‐ion battery (FIB) and bromide‐ion battery (BIB) configurations, a universal strategy for designing multi‐anion storage systems through carrier‐specific coordination regulation is established.