Tailoring the Coordination Microenvironment of Polymolybdate within a Metal–Organic Coordination System for Enhanced Capacitive Activity

The design of a low-cost and efficient electrode material is crucial for electrochemical energy storage. Effectual utilization of polymolybdate as an electrode material for a supercapacitor is promising. Meanwhile, the coordination microenvironments of polymolybdate sho potential effects on its performance. Herein, we designed and synthesized four polymolybdate-based metal–organic complexes using a structure design strategy. Their structures were characterized and analyzed using single crystallographic data. The theoretical calculations revealed that the coordination microenvironments of polymolybdate play a vital role in the hydrogen ions migration. High H adsorption capacity can obviously boost the electrochemical activity. The 1-based glassy carbon electrode showed the highest specific capacitance value of 1739.4 F·g–1 at the current density of 1 A·g–1. Meanwhile, the carbon cloth-based electrode fabricated by complex 1 (1/CC) also displayed a high capacitance performance. A hybrid supercapacitor was assembled using the 1/CC electrodes and showed a high energy density of 29.0 Wh kg–1 at the power density of 0.80 kW kg–1.