Polarization Regulation of Alkali-Treated Metal–Organic Frameworks for Dual-Functional Dielectrics

Coordination bond breakage and rearrangement offer a previously unexplored route to enhance the dielectric properties of metal–organic frameworks (MOFs). Here, we introduce a controlled alkali-treatment strategy to regulate polarization and energy storage in 2D M-TA MOFs (M = Ni, Co, NiCo; TA = terephthalate). Hydrolysis of metal nodes by OH⁻ generates ionic species and is thus prone to forming to architectures that amplify polarization. Co-TA derivatives treated for 16 min exhibit a dielectric constant of ε ≈ 27.8, ca. 4×higher than the pristine framework, while Ni-TA and NiCo-TA reveal improvements owing to stronger metal–ligand coupling. Thin films of NiCo-TA-2 display ultralow leakage currents (< 10⁻¹¹ A·cm⁻²) and robust mechanical performance (Young's modulus ≈ 0.92 GPa), highlighting their promise as high-κ gate dielectrics. When integrated into PVDF composites, treated MOFs deliver energy storage densities up to 2.74 J·cm⁻³, comparable to leading non-ferroelectric polymers. (Biaxially oriented polypropylene, a general commercial dielectric film, whose energy storage density down to 0.3 J·cm⁻³ and 5 MV/cm). These findings establish coordination-bond rearrangement as a powerful design principle for dielectric optimization in MOFs, offering a route to mitigate polarization–conductivity trade-offs and expand their applicability in advanced electronic and energy-storage technologies.