Dendritic-honeycomb porous polyoxometalate/MXene films for supercapacitor applications

Designing advanced porous electrode materials with enhanced ion/electron transport pathways and structural integrity is of great importance for next-generation flexible energy storage devices. This work presents dendritic-honeycomb hierarchical porous electrodes using POM/MXene complexes inspired by natural structures. FeMo-POM clusters are grown on MXene nanosheets and self-assembled into 3D porous membranes via the breath figure method. The unique structure combines interconnected dendritic channels and honeycomb-like pores, suppressing MXene restacking, enhancing active site exposure, and creating abundant electrolyte reservoirs. Benefiting from the hierarchical porous structure and the conductive network of POM/MXene, the resulting membranes exhibit superior electrochemical performance, markedly outperforming individual components and the flat counterparts. Furthermore, the porous architecture serves as an ideal scaffold for active materials deposition. After electrochemical deposition of polypyrrole (PPy), the porous POM/MXene/PPy achieves a high specific capacitance of 1074.75 F g −1 (0.3 A g −1 ) with nearly 80 % retention over 7000 cycles. The assembled flexible quasi-solid-state symmetric supercapacitor (FQSSC) delivers an energy density of 40.83 Wh kg −1 at a power density of 125.0 W kg −1 , shows excellent flexibility, and operates reliably across a wide temperature range. It can light multiple LEDs and power small electronic devices, demonstrating its practical applicability. This work provides a scalable and versatile pathway for next-generation flexible energy storage devices.