Polyoxometalate Imide‐Linked Molecules, Covalent Organic Polymers, and Frameworks: Dimensionality Effects on Supercapacitors Performance

Abstract Efficient and durable energy storage materials are essential to meet the increasing demand for renewable energy technologies. However, existing materials often encounter trade‐offs among energy density, power density, and cycling stability. To overcome these limitations, a 2D imide‐linked polyoxometalate‐covalent organic framework (i‐POCOF) is introduced. This hybrid material combines the redox activity of polyoxometalates (POMs) with the structural adaptability of covalent organic frameworks (COFs). Complementarily, 0D imide‐functionalized POM‐molecule and 1D POM‐polymer systems are investigated, enabling a systematic evaluation of how dimensionality affects their physicochemical properties and electrochemical performance. By increasing dimensionality, the hybrids exhibit improved surface area ranging from 107 m² g⁻¹ for 0D to 257 m² g⁻¹ for 2D, and optimized porosity (average pore size from 1.9 nm for 0D to 3.7 nm for 2D), resulting in enhanced ion diffusion and charge transport. In particular, 2D i‐POCOF exhibits remarkable electrochemical performance, achieving a specific capacitance of 132 F g⁻¹, energy density of 73.3 Wh kg⁻¹, and power density of 0.9 kW kg⁻¹, with only 6% capacitance loss after 5000 cycles. These findings highlight the potential of POM hybrids as high‐performance and stable energy storage hybrids, providing a promising pathway to overcome current limitations in electrode materials.