One-Dimensional POM-Based Material Combining Proton Conductivity and Supercapacitor Performance: Synthesis, Characterization, and Performance Study

To address the performance deficiencies of conventional energy materials in proton conduction and energy storage, a one-dimensional hourglass-shaped P 4 Mo 6 -based polyoxometalate material was designed and synthesized, with the chemical formula (H 2 dpe) 4 [Fe 2 (H 3 P 4 Mo 6 O 31 ) 2 ]·6H 2 O (denoted as CUST-580, dpe = 1,2-bis(4-pyridyl)ethane). P 4 Mo 6 clusters were interconnected via Fe ions to form a one-dimensional chain. In this structure, the terminal oxygen atoms of the clusters, free water molecules, and nitrogen atoms of the organic ligands collectively establish a dense hydrogen-bonding network. Proton conduction tests demonstrated that under the conditions of 90 °C and 98% relative humidity, the material achieved a conductivity of 4.01 × 10 –3 S cm –1, which followed the Grotthuss conduction mechanism. It also retained structural integrity and long-term stability under various environmental conditions. When CUST-580 was mixed with carbon black and then loaded onto carbon cloth, it displayed typical pseudocapacitive behavior in the mixed electrolyte. At a current density of 1 A g –1, the specific capacitance of CUST-580 reached 361 F g –1, and the capacitance retention rate remained 85.21% after 1500 cycles. This material realized the synergistic optimization of proton conduction and supercapacitor performance, providing new candidate materials and design concepts for the development of high-performance energy conversion and storage devices.