Dual‐Vacancy‐Driven Ion Channel and Locking Effects in LDHs for High‐Rate, Long‐Life Chloride Ion Batteries

ABSTRACT

Two‐dimensional (2D) transition‐metal compounds often suffer from the dissolution of active transition metals and structural collapse during electrochemical cycling. Herein, a sequential acid‐base regulation strategy is proposed to construct Zn and Al vacancies within layered double hydroxide (LDH) laminates, yielding a defect‐engineered NiZnFeAl‐V _Zn V _Al ‐Cl LDH. Benefiting from the synergistic effect of dual vacancies, LDH concurrently achieves “ion channel” and “ion locking” functionalities. The “ion channel” mechanism arises from vacancy‐induced disruption of the intrinsic c ‐axis transport barrier and the expansion of interlayer galleries into a three‐dimensional interconnected diffusion network, significantly enhancing Cl ⁻ diffusion. Meanwhile, the “ion locking” effect suppresses the Jahn–Teller distortion of Ni ³⁺ by strengthening metal‐oxygen bonds and inducing inherent local lattice distortions from cation defects, thereby preventing active‐metal dissolution and preserving structural integrity. Density functional theory (DFT) calculations further reveal that dual vacancies enhance the electronic density of states near the Fermi level, significantly improving conductivity and charge transfer efficiency. As a result, the NiZnFeAl‐V _Zn V _Al ‐Cl LDH delivers outstanding cycling stability, maintaining 99.8 mAh g ⁻¹ after 1950 cycles at 150 mA g ⁻¹ . This work provides comprehensive mechanistic insights into vacancy‐mediated performance enhancement in LDH and establishes a new perspective for exploiting defect chemistry in 2D materials toward advanced energy storage applications.